Blackrock Financial Institutions Series Trust

07/02/2026 | Press release | Distributed by Public on 07/02/2026 09:49

Annual Report by Investment Company (Form N-CSR)

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM N-CSR
CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT INVESTMENT COMPANIES
Investment Company Act file number:
811-03189
Name of Fund:
BlackRock Financial Institutions Series Trust
BlackRock Summit Cash Reserves Fund
Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809
Name and address of agent for service: John M. Perlowski, Chief Executive Officer, BlackRock Financial Institutions Series Trust, 50 Hudson Yards, New York, NY 10001
Registrant's telephone number, including area code:
(800) 441-7762
Date of fiscal year end:
4/30/2026
Date of reporting period:
4/30/2026
Item 1 - Report to Stockholders
(a) The Report to Shareholders is attached herewith

BlackRock Summit Cash Reserves Fund

Institutional Shares | MSIXX

Annual Shareholder Report - April 30, 2026

This annual shareholder report contains important information about BlackRock Summit Cash Reserves Fund (the "Fund") for the period of May 1, 2025 to April 30, 2026. You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441-7762.
What were the Fund costs for the last year ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment 		Costs paid as a percentage of a
$10,000 investment
Institutional Shares $43 0.42%
Key Fund statistics
Net Assets $1,137,763,250
Number of Portfolio Holdings 149
Net Investment Advisory Fees $4,315,234
Current seven-day yields as of April 30, 2026 (The 7-Day SEC Yield may differ from the 7-Day Yield shown due to
the fact that the 7-Day SEC Yield excludes distributed capital gains.)
7-Day SEC Yield 3.29%
7-Day Yield 3.29%
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Repurchase Agreements 45.6 %
U.S. Treasury Obligations 31.5 %
U.S. Government Sponsored Agency Securities 23.4 %
Liabilities in Excess of Other Assets (0.5 )
Past performance is not an indication of future results. Visit blackrock.com for more recent yield information.
Additional information
If you wish to view additional information about the Fund, including but not limited to financial statements, the Fund's prospectus, and proxy voting policies and procedures, please visit blackrock.com/fundreports. For proxy voting records, visit blackrock.com/proxyrecords.
Householding
The Fund will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called "householding" and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the Transfer Agent at (800) 441-7762.
©2026 BlackRock, Inc. or its affiliates. All rights reserved. BLACKROCK is a registered trademark of BlackRock, Inc. or its affiliates.
BlackRock Summit Cash Reserves Fund
Institutional Shares | MSIXX
Annual Shareholder Report - April 30, 2026
MSIXX-04/26-AR

BlackRock Summit Cash Reserves Fund

Investor A Shares | MSAXX

Annual Shareholder Report - April 30, 2026

This annual shareholder report contains important information about BlackRock Summit Cash Reserves Fund (the "Fund") for the period of May 1, 2025 to April 30, 2026. You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441-7762.
What were the Fund costs for the last year ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment 		Costs paid as a percentage of a
$10,000 investment
Investor A Shares $43 0.42%
Key Fund statistics
Net Assets $1,137,763,250
Number of Portfolio Holdings 149
Net Investment Advisory Fees $4,315,234
Current seven-day yields as of April 30, 2026 (The 7-Day SEC Yield may differ from the 7-Day Yield shown due to
the fact that the 7-Day SEC Yield excludes distributed capital gains.)
7-Day SEC Yield 3.29%
7-Day Yield 3.29%
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Repurchase Agreements 45.6 %
U.S. Treasury Obligations 31.5 %
U.S. Government Sponsored Agency Securities 23.4 %
Liabilities in Excess of Other Assets (0.5 )
Past performance is not an indication of future results. Visit blackrock.com for more recent yield information.
Additional information
If you wish to view additional information about the Fund, including but not limited to financial statements, the Fund's prospectus, and proxy voting policies and procedures, please visit blackrock.com/fundreports. For proxy voting records, visit blackrock.com/proxyrecords.
Householding
The Fund will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called "householding" and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the Transfer Agent at (800) 441-7762.
©2026 BlackRock, Inc. or its affiliates. All rights reserved. BLACKROCK is a registered trademark of BlackRock, Inc. or its affiliates.
BlackRock Summit Cash Reserves Fund
Investor A Shares | MSAXX
Annual Shareholder Report - April 30, 2026
MSAXX-04/26-AR

BlackRock Summit Cash Reserves Fund

Investor C Shares | MCBXX

Annual Shareholder Report - April 30, 2026

This annual shareholder report contains important information about BlackRock Summit Cash Reserves Fund (the "Fund") for the period of May 1, 2025 to April 30, 2026. You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441-7762.
What were the Fund costs for the last year ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment 		Costs paid as a percentage of a
$10,000 investment
Investor C Shares $119 1.17%
Key Fund statistics
Net Assets $1,137,763,250
Number of Portfolio Holdings 149
Net Investment Advisory Fees $4,315,234
Current seven-day yields as of April 30, 2026 (The 7-Day SEC Yield may differ from the 7-Day Yield shown due to
the fact that the 7-Day SEC Yield excludes distributed capital gains.)
7-Day SEC Yield 2.54%
7-Day Yield 2.54%
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Repurchase Agreements 45.6 %
U.S. Treasury Obligations 31.5 %
U.S. Government Sponsored Agency Securities 23.4 %
Liabilities in Excess of Other Assets (0.5 )
Past performance is not an indication of future results. Visit blackrock.com for more recent yield information.
Additional information
If you wish to view additional information about the Fund, including but not limited to financial statements, the Fund's prospectus, and proxy voting policies and procedures, please visit blackrock.com/fundreports. For proxy voting records, visit blackrock.com/proxyrecords.
Householding
The Fund will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called "householding" and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the Transfer Agent at (800) 441-7762.
©2026 BlackRock, Inc. or its affiliates. All rights reserved. BLACKROCK is a registered trademark of BlackRock, Inc. or its affiliates.
BlackRock Summit Cash Reserves Fund
Investor C Shares | MCBXX
Annual Shareholder Report - April 30, 2026
MCBXX-04/26-AR

(b) Not Applicable

Item 2 -

Code of Ethics - The registrant (or the "Fund") has adopted a code of ethics, as of the end of the period covered by this report, applicable to the registrant's principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. During the period covered by this report, the code of ethics was amended to update certain information and to make other non-material changes. During the period covered by this report, there have been no waivers granted under the code of ethics. The registrant undertakes to provide a copy of the code of ethics to any person upon request, without charge, who calls 1-800-441-7762.

Item 3 -

Audit Committee Financial Expert - The registrant's board of trustees (the "board of trustees"), has determined that (i) the registrant has the following audit committee financial experts serving on its audit committee and (ii) each audit committee financial expert is independent:

Neil A. Cotty

Henry R. Keizer

Kenneth L. Urish

Claire A. Walton

Under applicable securities laws, a person determined to be an audit committee financial expert will not be deemed an "expert" for any purpose, including without limitation for the purposes of Section 11 of the Securities Act of 1933, as a result of being designated or identified as an audit committee financial expert. The designation or identification of a person as an audit committee financial expert does not impose on such person any duties, obligations, or liabilities greater than the duties, obligations, and liabilities imposed on such person as a member of the audit committee and board of trustees in the absence of such designation or identification. The designation or identification of a person as an audit committee financial expert does not affect the duties, obligations, or liability of any other member of the audit committee or board of trustees.

Item 4 -

Principal Accountant Fees and Services

The following table presents fees billed by Deloitte & Touche LLP ("D&T") in each of the last two fiscal years for the services rendered to the Fund:

(a) Audit Fees

(b) Audit-Related

Fees1

(c) Tax Fees2 (d) All Other Fees
Entity Name

 Current 
Fiscal

Year

End

 Previous 

Fiscal

Year

End

 Current 

Fiscal

Year

End

 Previous 

Fiscal

Year

End

 Current 

Fiscal

Year

End

 Previous 

Fiscal

Year

End

 Current 

Fiscal

Year

End

 Previous 

Fiscal

Year

End

BlackRock Summit Cash Reserves Fund $28,634 $28,495 $0 $0 $9,900 $9,900 $596 $407

The following table presents fees billed by D&T that were required to be approved by the registrant's audit committee (the "Committee") for services that relate directly to the operations or financial reporting of the Fund and that are rendered on behalf of BlackRock Advisors, LLC (the "Investment Adviser" or "BlackRock") and entities controlling, controlled by, or under common control with BlackRock (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser) that provide ongoing services to the Fund ("Affiliated Service Providers"):

Current Fiscal Year End Previous Fiscal Year End

(b) Audit-Related Fees1

$0 $0

(c) Tax Fees2

$0 $0

(d) All Other Fees3

$2,277,000 $2,149,000

1 The nature of the services includes assurance and related services reasonably related to the performance of the audit or review of financial statements not included in Audit Fees, including accounting consultations, agreed-upon procedure reports, attestation reports, comfort letters, out-of-pocket expenses and internal control reviews not required by regulators.

2 The nature of the services includes tax compliance and/or tax preparation, including services relating to the filing or amendment of federal, state or local income tax returns, regulated investment company qualification reviews, taxable income and tax distribution calculations.

3 Non-audit fees of $2,277,000 and $2,149,000 for the current fiscal year and previous fiscal year, respectively, were paid to the Fund's principal accountant in their entirety by BlackRock, in connection with services provided to the Affiliated Service Providers of the Fund and of certain other funds sponsored and advised by BlackRock or its affiliates for a service organization review and an accounting research tool subscription. These amounts represent aggregate fees paid by BlackRock and were not allocated on a per fund basis.

(e)(1) Audit Committee Pre-Approval Policies and Procedures:

The Committee has adopted policies and procedures with regard to the pre-approval of services. Audit, audit-related and tax compliance services provided to the registrant on an annual basis require specific pre-approval by the Committee. The Committee also must approve other non-audit services provided to the registrant and those non-audit services provided to the Investment Adviser and Affiliated Service Providers that relate directly to the operations and the financial reporting of the registrant. Certain of these non-audit services that the Committee believes are (a) consistent with the Securities and Exchange Commission's auditor independence rules and (b) routine and recurring services that will not impair the independence of the independent accountants may be approved by the Committee without consideration on a specific case-by-case basis ("general pre-approval"). The term of any general pre-approval is 12 months from the date of the pre-approval, unless the Committee provides for a different period. Tax or other non-audit services provided to the registrant which have a direct impact on the operations or financial reporting of the registrant will only be deemed pre-approved provided that any individual project does not exceed $10,000 attributable to the registrant or $50,000 per project. For this purpose, multiple projects will be aggregated to determine if they exceed the previously mentioned cost levels.

Any proposed services exceeding the pre-approved cost levels will require specific pre-approval by the Committee, as will any other services not subject to general pre-approval (e.g., unanticipated but permissible services). The Committee is informed of each service approved subject to general pre-approval at the next regularly scheduled in-person board meeting. At this meeting, an analysis of such services is presented to the Committee for ratification. The Committee may delegate to the Committee Chairman the authority to approve the provision of and fees for any specific engagement of permitted non-audit services, including services exceeding pre-approved cost levels.

(e)(2) None of the services described in each of Items 4(b) through (d) were approved by the Committee pursuant to the de minimis exception in paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X.

(f) Not Applicable

(g) The aggregate non-audit fees, defined as the sum of the fees shown under "Audit-Related Fees," "Tax Fees" and "All Other Fees," paid to the accountant for services rendered by the accountant to the registrant, the Investment Adviser and the Affiliated Service Providers were:

Entity Name

Current

Fiscal Year

End

Previous

Fiscal Year

End

BlackRock Summit Cash Reserves Fund $10,496 $10,307

Additionally, the amounts billed by D&T in connection with services provided to the Affiliated Service Providers of the Fund and of other funds sponsored and advised by BlackRock or its affiliates during the current and previous fiscal years for a service organization review and an accounting research tool subscription were:

Current Fiscal Year End Previous Fiscal Year End

$2,277,000

$2,149,000

These amounts represent aggregate fees paid by BlackRock and were not allocated on a per fund basis.

(h) The Committee has considered and determined that the provision of non-audit services that were rendered to the Investment Adviser and the Affiliated Service Providers that were not pre-approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is compatible with maintaining the principal accountant's independence.

(i) Not Applicable

(j) Not Applicable

Item 5 -

Audit Committee of Listed Registrant - Not Applicable

Item 6 -

Investments

(a) The registrant's Schedule of Investments is included as part of the Financial Statements and Financial Highlights for Open-End Management Investment Companies filed under Item 7 of this Form.

(b) Not Applicable due to no such divestments during the semi-annual period covered since the previous Form N-CSR filing.

Item 7 -

Financial Statements and Financial Highlights for Open-End Management Investment Companies

(a) The registrant's Financial Statements are attached herewith.

(b) The registrant's Financial Highlights are attached herewith.

 
April 30, 2026 
2026 Annual Financial Statements
and Additional Information
 
BlackRock Financial Institutions Series Trust
• BlackRock Summit Cash Reserves Fund
 
Not FDIC Insured • May Lose Value • No Bank Guarantee
Table of Contents 
Page  
Schedule of Investments
3
Statement of Assets and Liabilities
6
Statement of Operations
8
Statements of Changes in Net Assets
9
Financial Highlights
10
Notes to Financial Statements
13
Report of Independent Registered Public Accounting Firm
18
Important Tax Information
19
Additional Information
20
Glossary of Terms Used in these Financial Statements
22
2
Schedule of Investments
April 30, 2026
BlackRock Summit Cash Reserves Fund
(Percentages shown are based on Net Assets)
 
Security
Par
(000)
Value
Short-Term Securities
U.S. Government Sponsored Agency Securities - 23.4%
Fannie Mae(a)
3.72%, 04/06/28
$
5,200
$ 5,200,000
(1-day SOFR + 0.08%), 3.72%, 01/07/28
6,355
6,355,444
(1-day SOFR + 0.09%), 3.73%, 02/02/28
1,200
1,200,000
(1-day SOFR + 0.09%), 3.73%, 03/06/28
2,600
2,600,000
(1-day SOFR + 0.12%), 3.76%, 07/29/26
7,240
7,240,000
(1-day SOFR + 0.14%), 3.78%, 08/21/26
2,200
2,200,000
(1-day SOFR + 0.14%), 3.78%, 10/23/26
2,930
2,930,000
(1-day SOFR + 0.14%), 3.78%, 11/20/26
3,700
3,700,000
(1-day SOFR + 0.14%), 3.78%, 12/11/26
2,900
2,900,000
Federal Farm Credit Banks Funding Corp.(a)
(1-day SOFR + 0.00%), 3.64%, 06/12/26
6,200
6,200,000
(1-day SOFR + 0.04%), 3.68%, 10/20/26
7,095
7,095,000
(1-day SOFR + 0.04%), 3.68%, 11/19/26
419
419,000
(1-day SOFR + 0.04%), 3.68%, 01/20/27
3,085
3,085,000
(1-day SOFR + 0.04%), 3.68%, 05/10/27
2,640
2,640,000
(1-day SOFR + 0.05%), 3.69%, 11/06/26
2,060
2,060,000
(1-day SOFR + 0.05%), 3.69%, 03/15/27
1,630
1,630,000
(1-day SOFR + 0.05%), 3.69%, 04/19/27
470
470,000
(1-day SOFR + 0.05%), 3.69%, 05/24/27
1,455
1,455,000
(1-day SOFR + 0.06%), 3.70%, 05/24/27
1,275
1,275,000
(1-day SOFR + 0.06%), 3.70%, 07/23/27
875
875,000
(1-day SOFR + 0.07%), 3.71%, 03/05/27
11,205
11,205,000
(1-day SOFR + 0.07%), 3.71%, 03/26/27
990
990,000
(1-day SOFR + 0.08%), 3.72%, 02/01/27
2,500
2,500,000
(1-day SOFR + 0.08%), 3.72%, 11/23/27
340
340,000
(1-day SOFR + 0.09%), 3.73%, 01/27/27
1,025
1,025,000
(1-day SOFR + 0.09%), 3.73%, 02/09/28
700
700,000
(1-day SOFR + 0.09%), 3.73%, 03/16/28
1,200
1,200,000
(1-day SOFR + 0.09%), 3.73%, 03/24/28
3,185
3,185,000
(1-day SOFR + 0.09%), 3.73%, 04/10/28
760
760,000
(1-day SOFR + 0.10%), 3.74%, 06/24/26
500
500,000
(1-day SOFR + 0.10%), 3.74%, 06/26/26
1,290
1,290,000
(1-day SOFR + 0.11%), 3.75%, 11/19/27
1,110
1,110,000
(1-day SOFR + 0.13%), 3.77%, 10/22/27
587
587,000
(1-day SOFR + 0.14%), 3.78%, 10/15/26
7,400
7,399,813
(1-day SOFR + 0.14%), 3.78%, 12/23/26
700
700,000
(1-day SOFR + 0.14%), 3.78%, 12/30/26
600
600,000
(3-mo. U.S. Treasury money market yield + 0.27%),
3.91%, 10/16/26
4,000
4,000,000
Federal Home Loan Bank Discount Notes(b)
3.55%, 06/24/26
3,870
3,849,712
3.56%, 07/08/26
1,200
1,192,073
3.55%, 07/10/26
3,840
3,813,956
3.58%, 07/13/26
3,870
3,842,416
3.63%, 07/17/26
5,605
5,562,825
3.61%, 07/31/26
4,500
4,459,614
3.61%, 08/05/26
5,000
4,952,733
3.60%, 08/21/26
400
395,598
3.60%, 08/28/26
600
592,985
3.57%, 09/14/26
3,800
3,749,827
3.67%, 11/27/26
1,450
1,419,635
3.68%, 12/31/26
4,020
3,922,321
Federal Home Loan Banks
3.88%, 09/25/26
2,700
2,700,000
3.50%, 01/11/27
7,740
7,731,278
3.85%, 04/09/27
5,100
5,100,000
(1-day SOFR + 0.00%), 3.64%, 05/18/26(a)
3,900
3,900,000
(1-day SOFR + 0.00%), 3.64%, 05/19/26(a)
2,600
2,600,000
(1-day SOFR + 0.00%), 3.64%, 06/08/26(a)
2,900
2,899,967
Security
Par
(000)
Value
U.S. Government Sponsored Agency Securities (continued)
Federal Home Loan Banks (continued)
(1-day SOFR + 0.00%), 3.64%, 06/16/26(a)
$
2,600
$ 2,600,000
(1-day SOFR + 0.00%), 3.64%, 06/18/26(a)
2,500
2,500,000
(1-day SOFR + 0.00%), 3.64%, 06/22/26(a)
3,950
3,950,000
(1-day SOFR + 0.00%), 3.64%, 06/23/26(a)
2,900
2,900,000
(1-day SOFR + 0.00%), 3.64%, 06/25/26(a)
1,315
1,315,000
(1-day SOFR + 0.00%), 3.64%, 07/02/26(a)
1,715
1,714,969
(1-day SOFR + 0.00%), 3.64%, 07/07/26(a)
1,300
1,300,000
(1-day SOFR + 0.01%), 3.65%, 05/05/26(a)
2,590
2,590,000
(1-day SOFR + 0.01%), 3.65%, 05/20/26(a)
1,200
1,200,000
(1-day SOFR + 0.01%), 3.65%, 06/02/26(a)
2,590
2,590,000
(1-day SOFR + 0.01%), 3.65%, 06/23/26(a)
2,550
2,550,000
(1-day SOFR + 0.01%), 3.65%, 07/21/26(a)
3,930
3,930,000
(1-day SOFR + 0.01%), 3.65%, 07/22/26(a)
1,300
1,300,000
(1-day SOFR + 0.01%), 3.65%, 07/24/26(a)
2,630
2,630,000
(1-day SOFR + 0.01%), 3.65%, 07/28/26(a)
1,300
1,300,000
(1-day SOFR + 0.01%), 1.00%, 08/04/26(a)
2,690
2,690,000
(1-day SOFR + 0.01%), 3.65%, 08/18/26(a)
600
599,990
(1-day SOFR + 0.01%), 3.65%, 08/19/26(a)
1,320
1,320,000
(1-day SOFR + 0.01%), 3.65%, 08/21/26(a)
9,210
9,210,000
(1-day SOFR + 0.01%), 3.65%, 08/24/26(a)
1,315
1,315,000
(1-day SOFR + 0.01%), 3.65%, 09/04/26(a)
1,300
1,299,955
(1-day SOFR + 0.01%), 3.65%, 09/08/26(a)
3,900
3,900,000
(1-day SOFR + 0.02%), 3.66%, 06/18/26(a)
2,620
2,620,000
(1-day SOFR + 0.02%), 3.66%, 07/17/26(a)
2,620
2,620,000
(1-day SOFR + 0.02%), 1.00%, 09/03/26(a)
2,690
2,690,000
(1-day SOFR + 0.02%), 3.66%, 10/06/26(a)
3,900
3,900,000
(1-day SOFR + 0.03%), 3.67%, 05/28/26(a)
1,400
1,400,000
(1-day SOFR + 0.03%), 3.67%, 06/04/26(a)
2,800
2,800,000
(1-day SOFR + 0.03%), 3.67%, 06/30/26(a)
1,360
1,360,000
(1-day SOFR + 0.03%), 3.67%, 07/02/26(a)
2,995
2,995,000
(1-day SOFR + 0.03%), 3.67%, 11/03/26(a)
2,500
2,500,000
(1-day SOFR + 0.03%), 3.67%, 11/23/26(a)
5,250
5,250,000
(1-day SOFR + 0.03%), 3.67%, 11/30/26(a)
1,800
1,800,000
(1-day SOFR + 0.03%), 3.67%, 01/04/27(a)
1,200
1,200,000
(1-day SOFR + 0.07%), 3.71%, 03/25/27(a)
2,170
2,170,000
(1-day SOFR + 0.08%), 3.72%, 01/24/28(a)
3,100
3,100,000
(1-day SOFR + 0.10%), 3.74%, 06/26/26(a)
3,590
3,590,000
(1-day SOFR + 0.10%), 3.74%, 03/18/27(a)
2,910
2,910,000
Federal Home Loan Mortgage Corp.(a)
(1-day SOFR + 0.12%), 3.76%, 05/05/27
1,700
1,700,000
(1-day SOFR + 0.14%), 3.78%, 09/23/26
2,400
2,400,000
(1-day SOFR + 0.14%), 3.78%, 10/16/26
1,800
1,800,000
265,816,111
U.S. Treasury Obligations - 31.5%
U.S. Treasury Bills(b)
4.11%, 05/14/26
8,814
8,801,491
3.65%, 05/19/26 - 09/10/26
13,270
13,146,862
3.70%, 05/26/26
600
598,490
3.79%, 05/28/26
17,868
17,818,886
3.75%, 06/04/26
22,938
22,859,253
4.03%, 06/11/26
9,274
9,232,944
3.61%, 06/18/26 - 08/20/26
32,087
31,788,036
3.60%, 06/25/26
16,754
16,664,701
3.59%, 07/09/26
5,600
5,562,702
3.74%, 08/06/26 - 09/03/26
41,148
40,640,510
3.69%, 08/11/26
24,270
24,022,446
3.71%, 10/01/26
190
187,093
3.73%, 10/08/26
4,132
4,065,613
3.52%, 12/24/26 - 02/18/27
32,842
32,066,403
3.63%, 03/18/27
11,100
10,755,072
Schedule of Investments 3
Schedule of Investments (continued)
April 30, 2026
BlackRock Summit Cash Reserves Fund
(Percentages shown are based on Net Assets)
Security
Par
(000)
Value
U.S. Treasury Obligations (continued)
U.S. Treasury Notes
1.63%, 05/15/26
$
1,610
$ 1,608,551
0.88%, 06/30/26
510
507,336
4.63%, 06/30/26
3,740
3,742,805
(3-mo. U.S. Treasury money market yield + 0.18%),
3.83%, 07/31/26(a)
7,775
7,773,977
(3-mo. U.S. Treasury money market yield + 0.21%),
3.85%, 10/31/26(a)
27,420
27,423,763
4.13%, 10/31/26 - 02/28/27
12,517
12,572,771
4.25%, 11/30/26 - 03/15/27
11,198
11,252,081
4.00%, 01/15/27
1,100
1,103,290
(3-mo. U.S. Treasury money market yield + 0.10%),
3.74%, 01/31/27(a)
21,635
21,634,530
2.50%, 03/31/27
1,100
1,089,921
3.88%, 03/31/27
4,500
4,512,745
2.75%, 04/30/27
980
970,753
3.75%, 04/30/27
3,040
3,040,501
0.50%, 05/31/27
1,300
1,254,832
2.63%, 05/31/27
200
197,508
(3-mo. U.S. Treasury money market yield + 0.16%),
3.80%, 07/31/27(a)
8,589
8,585,115
Security
Par
(000)
Value
U.S. Treasury Obligations (continued)
U.S. Treasury Notes (continued)
(3-mo. U.S. Treasury money market yield + 0.19%),
3.83%, 10/31/27(a)
$
10,521
$ 10,525,018
3.74%, 01/31/28(a)
2,700
2,699,956
358,705,955
Total Short-Term Securities -54.9%
(Cost: $624,522,066)
624,522,066
Total Repurchase Agreements - 45.6%
(Cost: $518,800,000)
518,800,000
Total Investments - 100.5%
(Cost: $1,143,322,066)
1,143,322,066
Liabilities in Excess of Other Assets - (0.5)%
(5,558,816
)
Net Assets - 100.0%
$ 1,137,763,250
 
(a)
Variable rate security. Interest rate resets periodically. The rate shown is the effective
interest rate as of period end. Security description also includes the reference rate and
spread if published and available.
(b)
Rates are the current rate or a range of current rates as of period end.
Repurchase Agreements 
Repurchase Agreements
Collateral
Counterparty
Coupon
Rate
Purchase
Date
Maturity
Date
Par
(000)
At Value
Proceeds
Including
Interest
Position
Original Par
Position
Received,
at Value
BNP Paribas S.A.
3.64
% 
04/30/26
05/01/26
$ 95,000
$ 95,000,000
$ 95,009,605
U.S. Treasury Obligation,
0.00% to 4.25%, due
7/15/26 to 8/15/46
$ 94,816,781
$ 96,900,000
BofA Securities, Inc.
3.64
04/30/26
05/01/26
15,000
15,000,000
15,001,517
U.S. Treasury Obligation,
0.00% to 4.13%, due
2/28/31 to 8/15/47
15,728,618
15,300,000
3.65
04/30/26
05/01/26
95,000
95,000,000
95,009,632
U.S. Government Sponsored
Agency Obligation, 2.04%
to 7.00%, due 6/15/31 to
4/20/56
136,792,500
96,900,000
Total BofA Securities, Inc.
$ 110,000,000
$ 112,200,000
J.P. Morgan Securities LLC
3.75
(a)
04/30/26
07/29/26
12,800
12,800,000
12,920,000
U.S. Government Sponsored
Agency Obligation, 0.20%
to 5.82%, due 9/20/30 to
6/15/50
96,207,284
13,439,520
3.64
04/30/26
05/01/26
112,000
112,000,000
112,011,324
U.S. Treasury Obligation,
3.88%, due 9/30/32
115,810,600
114,240,003
Total J.P. Morgan Securities LLC
$ 124,800,000
$ 127,679,523
Mizuho Securities USA, Inc.
3.65
04/30/26
05/01/26
92,000
92,000,000
92,009,328
U.S. Treasury Obligation,
4.00%, due 7/31/29
92,750,200
93,840,038
TD Securities (USA) LLC
3.64
04/30/26
05/01/26
97,000
97,000,000
97,009,808
U.S. Treasury Obligation,
4.13% to 4.63%, due
3/31/29 to 9/30/30
98,122,000
98,940,009
$ 518,800,000
$ 529,559,570
 
(a)
Variable rate security. Rate as of period end and maturity is the date the principal owed can be recovered through demand.
4
2026 BlackRock Annual Financial Statements and Additional Information
Schedule of Investments (continued)
April 30, 2026
BlackRock Summit Cash Reserves Fund
 
Fair Value Hierarchy as of Period End
Various inputs are used in determining the fair value of financial instruments at the measurement date. For a description of the input levels and information about the Fund's policy regarding valuation of financial instruments, refer to the Notes to Financial Statements.
The following table summarizes the Fund's financial instruments categorized in the fair value hierarchy. The breakdown of the Fund's financial instruments into major categories is disclosed in the Schedule of Investments above. 
Level 1
Level 2
Level 3
Total
Assets
Investments 
Short-Term Securities 
U.S. Government Sponsored Agency Securities
$ -
$ 265,816,111
$ -
$ 265,816,111
U.S. Treasury Obligations
-
358,705,955
-
358,705,955
Repurchase Agreements
-
518,800,000
-
518,800,000
$-
$1,143,322,066
$-
$1,143,322,066
See notes to financial statements.
Schedule of Investments 5
Statement of Assets and Liabilities April 30, 2026
 
BlackRock Summit
Cash Reserves
Fund
ASSETS
Investments, at value - unaffiliated(a)
$ 624,522,066
Cash
1,333,521
Repurchase agreements, at value(b)
518,800,000
Receivables:
Capital shares sold
11,956,055
Interest - unaffiliated
1,370,943
Prepaid expenses
178,634
Total assets
1,158,161,219
LIABILITIES
Payables:
Investments purchased
8,557,245
Accounting services fees
2,018
Capital shares redeemed
11,360,857
Custodian fees
7,450
Income dividend distributions
55,867
Investment advisory fees
347,878
Trustees' and Officer's fees
1,839
Other accrued expenses
16,790
Professional fees
39,515
Service and distribution fees
357
Transfer agent fees
8,153
Total liabilities
20,397,969
Commitments and contingent liabilities
NET ASSETS
$ 1,137,763,250
NET ASSETS CONSIST OF
Paid-in capital
$ 1,137,719,185
Accumulated earnings
44,065
NET ASSETS
$ 1,137,763,250
(a) Investments, at cost-unaffiliated
$624,522,066
(b) Repurchase agreements, at cost
$518,800,000
6
2026 BlackRock Annual Financial Statements and Additional Information
Statement of Assets and Liabilities  (continued)April 30, 2026
 
BlackRock Summit
Cash Reserves
Fund
NET ASSET VALUE
Institutional
Net assets
$ 148,574,924
Shares outstanding
148,594,062
Net asset value
$ 1.00
Shares authorized
Unlimited
Par value
$0.10
Investor A
Net assets
$ 988,027,131
Shares outstanding
988,158,934
Net asset value
$ 1.00
Shares authorized
Unlimited
Par value
$0.10
Investor C
Net assets
$ 1,161,195
Shares outstanding
1,161,431
Net asset value
$ 1.00
Shares authorized
Unlimited
Par value
$0.10
See notes to financial statements.
Statement of Assets and Liabilities 7
Statement of Operations Year Ended April 30, 2026
 
BlackRock Summit
Cash Reserves
Fund
INVESTMENT INCOME
Interest - unaffiliated
$45,823,591
Total investment income
45,823,591
EXPENSES
Investment advisory
5,654,704
Transfer agent - class specific
183,010
Professional
154,973
Registration
146,603
Accounting services
34,676
Custodian
32,009
Printing and postage
22,162
Trustees and Officer
16,427
Distribution - class specific
11,196
Miscellaneous
18,790
Total expenses excluding interest expense
6,274,550
Interest expense - unaffiliated
63
Total expenses
6,274,613
Less:
Fees waived and/or reimbursed by the Manager
(1,339,470
)
Transfer agent fees waived and/or reimbursed by the Manager - class specific
(180,673
)
Total expenses after fees waived and/or reimbursed
4,754,470
Net investment income
41,069,121
REALIZED AND UNREALIZED GAIN (LOSS)
Net realized gain from:
Investments - unaffiliated
34,020
Net realized and unrealized gain
34,020
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS
$41,103,141
See notes to financial statements.
8
2026 BlackRock Annual Financial Statements and Additional Information
Statements of Changes in Net Assets
 
BlackRock Summit
Cash Reserves Fund
Year Ended
04/30/26
Year Ended
04/30/25
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income
$41,069,121
$41,690,372
Net realized gain
34,020
30,108
Net increase in net assets resulting from operations
41,103,141
41,720,480
DISTRIBUTIONS TO SHAREHOLDERS(a)
Institutional
(4,957,478
)
(5,554,360
)
Investor A
(36,095,812
)
(36,122,547
)
Investor C
(43,627
)
(24,593
)
Decrease in net assets resulting from distributions to shareholders
(41,096,917
)
(41,701,500
)
CAPITAL SHARE TRANSACTIONS
Net increase in net assets derived from capital share transactions
69,803,326
271,264,369
NET ASSETS
Total increase in net assets
69,809,550
271,283,349
Beginning of year
1,067,953,700
796,670,351
End of year
$1,137,763,250
$1,067,953,700
 
(a)
Distributions for annual periods determined in accordance with U.S. federal income tax regulations.
See notes to financial statements.
Statements of Changes in Net Assets 9
Financial Highlights(For a share outstanding throughout each period)
 
BlackRock Summit Cash Reserves Fund
Institutional
Year Ended
04/30/26
Year Ended
04/30/25
Year Ended
04/30/24
Year Ended
04/30/23
Year Ended
04/30/22
Net asset value, beginning of year
$1.00
$1.00
$1.00
$1.00
$1.00
Net investment income
0.0364
0.0446
0.0491
0.0263
0.0001
Net realized and unrealized gain
0.0000
(a)
0.0000
(a)
0.0000
(a)
0.0000
(a)
0.0000
(a)
Net increase from investment operations
0.0364
0.0446
0.0491
0.0263
0.0001
Distributions(b)
From net investment income
(0.0364
)
(0.0446
)
(0.0491
)
(0.0263
)
(0.0001
)
From net realized gain
(0.0000
)(c)
(0.0000
)(c)
(0.0000
)(c)
(0.0000
)(c)
(0.0000
)(c)
Total distributions
(0.0364
)
(0.0446
)
(0.0491
)
(0.0263
)
(0.0001
)
Net asset value, end of year
$1.00
$1.00
$1.00
$1.00
$1.00
Total Return(d)
Based on net asset value
3.70
%
4.56
%
5.03
%
2.66
%
0.01
%
Ratios to Average Net Assets
Total expenses
0.57
%
0.56
%
0.59
%
0.59
%
0.60
%
Total expenses after fees waived and/or reimbursed
0.42
%
0.42
%
0.42
%
0.41
%
0.12
%
Net investment income
3.64
%
4.43
%
4.92
%
2.66
%
0.00
%(e)
Supplemental Data
Net assets, end of year (000)
$148,575
$142,088
$114,948
$97,307
$101,901
 
(a)
Amount is less than $0.00005 per share.
(b)
Distributions for annual periods determined in accordance with U.S. federal income tax regulations.
(c)
Amount is greater than $(0.00005) per share.
(d)
Where applicable, assumes the reinvestment of distributions.
(e)
Amount is less than 0.005%.
See notes to financial statements.
10
2026 BlackRock Annual Financial Statements and Additional Information
Financial Highlights (continued)(For a share outstanding throughout each period)
 
BlackRock Summit Cash Reserves Fund (continued)
Investor A
Year Ended
04/30/26
Year Ended
04/30/25
Year Ended
04/30/24
Year Ended
04/30/23
Year Ended
04/30/22
Net asset value, beginning of year
$1.00
$1.00
$1.00
$1.00
$1.00
Net investment income
0.0364
0.0446
0.0491
0.0263
0.0002
Net realized and unrealized gain
0.0000
(a)
0.0000
(a)
0.0000
(a)
0.0000
(a)
0.0000
(a)
Net increase from investment operations
0.0364
0.0446
0.0491
0.0263
0.0002
Distributions(b)
From net investment income
(0.0364
)
(0.0446
)
(0.0491
)
(0.0263
)
(0.0002
)
From net realized gain
(0.0000
)(c)
(0.0000
)(c)
(0.0000
)(c)
(0.0000
)(c)
(0.0000
)(c)
Total distributions
(0.0364
)
(0.0446
)
(0.0491
)
(0.0263
)
(0.0002
)
Net asset value, end of year
$1.00
$1.00
$1.00
$1.00
$1.00
Total Return(d)
Based on net asset value
3.70
%
4.56
%
5.03
%
2.66
%
0.02
%
Ratios to Average Net Assets
Total expenses
0.55
%
0.55
%
0.57
%
0.59
%
0.61
%
Total expenses after fees waived and/or reimbursed
0.42
%
0.42
%
0.42
%
0.41
%
0.10
%
Net investment income
3.63
%
4.42
%
4.92
%
2.74
%
0.01
%
Supplemental Data
Net assets, end of year (000)
$988,027
$924,184
$681,247
$484,690
$356,419
 
(a)
Amount is less than $0.00005 per share.
(b)
Distributions for annual periods determined in accordance with U.S. federal income tax regulations.
(c)
Amount is greater than $(0.00005) per share.
(d)
Where applicable, assumes the reinvestment of distributions.
See notes to financial statements.
Financial Highlights 11
Financial Highlights (continued)(For a share outstanding throughout each period)
 
BlackRock Summit Cash Reserves Fund (continued)
Investor C
Year Ended
04/30/26
Year Ended
04/30/25
Year Ended
04/30/24
Year Ended
04/30/23
Year Ended
04/30/22
Net asset value, beginning of year
$1.00
$1.00
$1.00
$1.00
$1.00
Net investment income
0.0289
0.0371
0.0416
0.0194
0.0002
Net realized and unrealized gain
0.0000
(a)
0.0000
(a)
0.0000
(a)
0.0000
(a)
0.0000
(a)
Net increase from investment operations
0.0289
0.0371
0.0416
0.0194
0.0002
Distributions(b)
From net investment income
(0.0289
)
(0.0371
)
(0.0416
)
(0.0194
)
(0.0002
)
From net realized gain
(0.0000
)(c)
(0.0000
)(c)
(0.0000
)(c)
(0.0000
)(c)
(0.0000
)(c)
Total distributions
(0.0289
)
(0.0371
)
(0.0416
)
(0.0194
)
(0.0002
)
Net asset value, end of year
$1.00
$1.00
$1.00
$1.00
$1.00
Total Return(d)
Based on net asset value
2.93
%
3.78
%
4.24
%
1.96
%
0.03
%
Ratios to Average Net Assets
Total expenses
1.56
%
1.53
%
1.35
%
1.35
%
1.46
%
Total expenses after fees waived and/or reimbursed
1.17
%
1.17
%
1.17
%
1.11
%
0.10
%
Net investment income
2.92
%
3.55
%
4.15
%
1.75
%
0.02
%
Supplemental Data
Net assets, end of year (000)
$1,161
$1,682
$475
$820
$948
 
(a)
Amount is less than $0.00005 per share.
(b)
Distributions for annual periods determined in accordance with U.S. federal income tax regulations.
(c)
Amount is greater than $(0.00005) per share.
(d)
Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.
See notes to financial statements.
12
2026 BlackRock Annual Financial Statements and Additional Information
Notes to Financial Statements
 
1.
ORGANIZATION
BlackRock Financial Institutions Series Trust (the "Trust") is registered under the Investment Company Act of 1940, as amended (the "1940 Act"), as an open-end management investment company.  The Trust is organized as a Massachusetts business trust.  BlackRock Summit Cash Reserves Fund (the "Fund") is a series of the Trust.  The Fund is classified as a diversified fund under the 1940 Act.
The Fund offers multiple classes of shares.  All classes of shares have identical voting, dividend, liquidation and other rights and are subject to the same terms and conditions, except that certain classes bear expenses related to the shareholder servicing and distribution of such shares.  Institutional Shares are sold without a sales charge and only to certain eligible investors.  Investor A Shares are generally sold with an initial sales charge, and may be subject to a contingent deferred sales charge ("CDSC") for certain redemptions where no initial sales charge was paid at the time of purchase. Investor C Shares may be subject to a 1.00% CDSC if redeemed within one year of purchase.  Investor A Shares are generally available through financial intermediaries. Investor C Shares are available only through exchanges and dividend and capital gain reinvestments by current holders.  Investor C Shares automatically convert to Investor A Shares after approximately eight years.  Each class has exclusive voting rights with respect to matters relating to its shareholder servicing and distribution expenditures.
The  Fund operates as a "government money market fund" under Rule 2a-7 under the 1940 Act. The Fund is not subject to discretionary liquidity fees.
The Fund, together with certain other registered investment companies advised by BlackRock Advisors, LLC (the "Manager") or its affiliates, is included in a complex of funds referred to as the BlackRock Multi-Asset Complex.
2.
SIGNIFICANT ACCOUNTING POLICIES
The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP"), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Fund is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:
Investment Transactions and Income Recognition:  For financial reporting purposes, investment transactions are recorded on the dates the transactions are executed.  Realized gains and losses on investment transactions are determined using the specific identification method.  Interest income, including amortization and accretion of premiums and discounts on debt securities, is recognized daily on an accrual basis.  Income, expenses and realized and unrealized gains and losses are allocated daily to each class based on its relative net assets.
Cash: The Fund may maintain cash at its custodian which, at times may exceed United States federally insured limits. The Fund may, at times, have outstanding cash disbursements that exceed deposited cash amounts at the custodian during the reporting period. The Fund is obligated to repay the custodian for any overdraft, including any related costs or expenses, where applicable. For financial reporting purposes, overdraft fees, if any, are included in interest expense in the Statement of Operations.
Distributions:  Distributions from net investment income are declared daily and paid monthly. Distributions of capital gains are distributed at least annually and are recorded on the ex-dividend dates.  The character and timing of distributions are determined in accordance with U.S. federal income tax regulations, which may differ from U.S. GAAP.
Indemnifications: In the normal course of business, the Fund enters into contracts that contain a variety of representations that provide general indemnification. The Fund's maximum exposure under these arrangements is unknown because it involves future potential claims against the Fund, which cannot be predicted with any certainty.
Other:  Expenses directly related to the Fund or its classes are charged to the Fund or the applicable class. Expenses directly related to the Fund and other shared expenses prorated to the Fund are allocated daily to each class based on its relative net assets or other appropriate methods. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods.
Segment Reporting: The Chief Financial Officer acts as the Fund's Chief Operating Decision Maker ("CODM") and is responsible for assessing performance and allocating resources with respect to the Fund. The CODM has concluded that the Fund operates as a single operating segment since the Fund has a single investment strategy as disclosed in its prospectus, against which the CODM assesses performance. The financial information provided to and reviewed by the CODM is presented within the Fund's financial statements.
Recent Accounting Standard: The Fund adopted Financial Accounting Standards Board Update 2023-09, Income Taxes (Topic 740) - Improvements to Income Tax Disclosures ("ASU 2023-09") during the period. ASU 2023-09 enhances income tax disclosures, including disclosure of income taxes paid disaggregated by jurisdiction. The Fund's adoption of the new standard did not have a material impact on financial statement disclosures and did not affect the Fund's financial position or results of operations.
3.
INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS
Investment Valuation Policies:  U.S. GAAP defines fair value as the price the Fund would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date.  The Fund's investments are valued under the amortized cost method which approximates current market value in accordance with Rule 2a-7 under the 1940 Act. Under this method, investments are valued at cost when purchased and, thereafter, a constant proportionate accretion of discounts and amortization of premiums are recorded until the maturity of the security. The Fund seeks to maintain its net asset value ("NAV") per share at $1.00, although there is no assurance that it will be able to do so on a continuing basis.
Notes to Financial Statements 13
Notes to Financial Statements  (continued)
 
Fair Value Hierarchy: Various inputs are used in determining the fair value of financial instruments at the measurement date. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three broad levels for financial reporting purposes as follows:
•Level 1 - Unadjusted price quotations in active markets/exchanges that the Fund has the ability to access for identical assets or liabilities;
•Level 2 - Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly; and
•Level 3 - Inputs that are unobservable and significant to the entire fair value measurement for the asset or liability (including the Valuation Committee's assumptions used in determining the fair value of financial instruments).
The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. The categorization of a value determined for financial instruments is based on the pricing transparency of the financial instruments and is not necessarily an indication of the risks associated with investing in those securities.
4.
SECURITIES AND OTHER INVESTMENTS
Repurchase Agreements: Repurchase agreements are commitments to purchase a security from a counterparty who agrees to repurchase the same security at a mutually agreed upon date and price. On a daily basis, the counterparty is required to maintain collateral subject to the agreement and in value no less than the agreed upon repurchase amount. Repurchase agreements may be traded bilaterally, in a tri-party arrangement or may be centrally cleared through a sponsoring agent. Subject to the custodial undertaking associated with a tri-party repurchase arrangement and for centrally cleared repurchase agreements, a third-party custodian maintains accounts to hold collateral for a fund and its counterparties. Typically, a fund and counterparty are not permitted to sell, re-pledge or use the collateral absent a default by the counterparty or the fund, respectively.
In the event the counterparty defaults and the fair value of the collateral declines, a fund could experience losses, delays and costs in liquidating the collateral.
Repurchase agreements are entered into by a fund under Master Repurchase Agreements (each, an "MRA"). The MRA permits the fund, under certain circumstances including an event of default (such as bankruptcy or insolvency), to offset payables and/or receivables with collateral held by and/or posted to the counterparty. As a result, one single net payment is created. Bankruptcy or insolvency laws of a particular jurisdiction may impose restrictions on or prohibitions against such a right of offset in the event of the MRA counterparty's bankruptcy or insolvency. Based on the terms of the MRA, the fund receives collateral with a market value in excess of the repurchase price at maturity. Upon a bankruptcy or insolvency of the MRA counterparty, the fund would recognize a liability with respect to such excess collateral. The liability reflects the fund's obligation under bankruptcy law to return the excess to the counterparty.
5.
INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES
Investment Advisory: The Trust, on behalf of the Fund, entered into an Investment Advisory Agreement with the Manager, the Fund's investment adviser and an indirect, majority-owned subsidiary of BlackRock, Inc. ("BlackRock"), to provide investment advisory and administrative services. The Manager is responsible for the management of the Fund's portfolio and provides the personnel, facilities, equipment and certain other services necessary to the operations of the Fund.
For such services, the Fund pays the Manager a monthly fee at an annual rate equal to 0.50% of the average daily value of the Fund's net assets.
Distribution Fees:  The Trust, on behalf of the Fund, entered into a Distribution Agreement and a Distribution Plan with BlackRock Investments, LLC ("BRIL"), an affiliate of the Manager. Pursuant to the Distribution Plan and in accordance with Rule 12b-1 under the 1940 Act, the Fund pays BRIL ongoing distribution fees. The fees are accrued daily and paid monthly at annual rates based upon the average daily net assets of the relevant share class of the Fund as follows: 
Share Class
Distribution Fees
Investor C
0.75
% 
BRIL and broker-dealers, pursuant to sub-agreements with BRIL, provide shareholder distribution services to the Fund. The ongoing distribution fee compensates BRIL and each broker-dealer for providing shareholder distribution related services to shareholders.
For the year ended April 30, 2026, the following table shows the class specific distribution fees borne directly by each share class of the Fund: 
Investor C
Distribution fees - class specific
$ 11,196
Transfer Agent:  Pursuant to written agreements, certain financial intermediaries, some of which may be affiliates, provide the Fund with sub-accounting, recordkeeping, sub-transfer agency and other administrative services with respect to servicing of underlying investor accounts. For these services, these entities receive an asset-based fee or an annual fee per shareholder account, which will vary depending on share class and/or net assets.  For the year ended April 30, 2026, the Fund did not pay any amounts to affiliates in return for these services.
14
2026 BlackRock Annual Financial Statements and Additional Information
Notes to Financial Statements  (continued)
 
The Manager maintains a call center that is responsible for providing certain shareholder services to the Fund. Shareholder services include responding to inquiries and processing purchases and sales based upon instructions from shareholders. For the year ended April 30, 2026, the Fund reimbursed the Manager the following amounts for costs incurred in running the call center, which are included in transfer agent - class specific in the Statement of Operations: 
Fund Name
Investor A
Investor C
Total
BlackRock Summit Cash Reserves Fund
$ 15,076
$ 3,250
$ 18,326
For the year ended April 30, 2026, the following table shows the class specific transfer agent fees borne directly by each share class of the Fund: 
Institutional
Investor A
Investor C
Total
Transfer agent fees - class specific
$ 44,915
$ 134,009
$ 4,086
$ 183,010
Other Fees:  For the year ended April 30, 2026, affiliates received CDSCs as follows: 
Fund Name
Investor A
Investor C
BlackRock Summit Cash Reserves Fund
$ 1,811
$ 64
Expense Limitations, Waivers and Reimbursements:  With respect to the Fund, the Manager contractually agreed to waive and/or reimburse fees or expenses in order to limit net total annual operating expenses, excluding interest expense, dividend expense, tax expense, acquired fund fees and expenses, and certain other fund expenses ("expense limitation"). The expense limitation as a percentage of average daily net assets is as follows: 
Share Class
Expense Limitation
Institutional
0.42
% 
Investor A
0.42
Investor C
1.17
The Manager has agreed not to reduce or discontinue the contractual expense limitations through June 30, 2027, unless approved by the Board, including a majority of the trustees who are not "interested persons" of the Trust, as defined in the 1940 Act ("Independent Trustees"), or by a vote of a majority of the outstanding voting securities of the Fund.  For the year ended April 30, 2026, the Manager waived and/or reimbursed investment advisory fees of $1,339,470 which is included in fees waived and/or reimbursed by the Manager in the Statement of Operations.
In addition, these amounts waived and/or reimbursed by the Manager are included in transfer agent fees waived and/or reimbursed by the Manager-class specific in the Statement of Operations. For the year ended April 30, 2026, class specific expense waivers and/or reimbursements were as follows: 
Institutional
Investor A
Investor C
Total
Transfer agent fees waived and/or reimbursed by the Manager - class specific
$ 43,974
$ 132,618
$ 4,081
$ 180,673
The Manager and BRIL have also voluntarily agreed to waive a portion of their respective management, investment advisory and distribution fees and/or reimburse operating expenses to enable the Fund to maintain minimum levels of daily net investment income if applicable. These amounts, if any, are reported in the Statement of Operations as fees waived and/or reimbursed by the Manager. The Manager and BRIL may discontinue the waiver and/or reimbursement at any time. For the year ended April 30, 2026, there were no fees waived and/or reimbursed by the Manager under this agreement.
Trustees and Officers:  Certain trustees and/or officers of the Trust are directors and/or officers of BlackRock or its affiliates. The Fund reimburses the Manager for a portion of the compensation paid to the Trust's Chief Compliance Officer, which is included in Trustees and Officer in the Statement of Operations.
6.
INCOME TAX INFORMATION
It is the Fund's policy to comply with the requirements of the Internal Revenue Code of 1986, as amended, applicable to regulated investment companies, and to distribute substantially all of its taxable income to its shareholders. Therefore, no U.S. federal income tax provision is required.
The Fund files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Fund's U.S. federal tax returns generally remains open for a period of three years after they are filed. The statutes of limitations on the Fund's state and local tax returns may remain open for an additional year depending upon the jurisdiction.
Management has analyzed tax laws and regulations and their application to the Fund as of April 30, 2026, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Fund's financial statements. Management's analysis is based on the tax laws and judicial and administrative interpretations thereof in effect as of the date of these financial statements, all of which are subject to change, possibly with retroactive effect, which may impact the Fund's NAV.
The tax character of distributions paid was as follows: 
Fund Name
Year Ended
04/30/26
Year Ended
04/30/25
BlackRock Summit Cash Reserves Fund
Ordinary income
$ 41,096,917
$ 41,701,500
Notes to Financial Statements 15
Notes to Financial Statements  (continued)
 
As of April 30, 2026, the tax components of accumulated earnings (loss) were as follows: 
Fund Name
Undistributed
Ordinary Income
Undistributed
Long-Term
Capital Gains
Total
BlackRock Summit Cash Reserves Fund
$ 42,093
$ 1,972
$ 44,065
As of April 30, 2026, gross unrealized appreciation and depreciation based on cost of investments (including short positions and derivatives, if any) for U.S. federal income tax purposes were as follows: 
Fund Name
Tax Cost
Gross Unrealized
Appreciation
Gross Unrealized
Depreciation
Net Unrealized
Appreciation
(Depreciation)
BlackRock Summit Cash Reserves Fund
$ 1,143,322,066
$ -
$ -
$ -
7.
PRINCIPAL RISKS
In the normal course of business, the Fund invests in securities or other instruments and may enter into certain transactions, and such activities subject the Fund to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation, tariffs or international tax treaties between various countries; or (iv) currency, interest rate or price fluctuations. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issues, recessions, or other events could have a significant impact on the Fund and its investments. The Fund's prospectus provides details of the risks to which the Fund is subject.
Counterparty Credit Risk: The Fund may be exposed to counterparty credit risk, or the risk that an entity may fail to or be unable to perform on its commitments related to unsettled or open transactions, including making timely interest and/or principal payments or otherwise honoring its obligations. The Fund manages counterparty credit risk by entering into transactions only with counterparties that the Manager believes have the financial resources to honor their obligations and by monitoring the financial stability of those counterparties. Financial assets, which potentially expose the Fund to market, issuer and counterparty credit risks, consist principally of financial instruments and receivables due from counterparties. The extent of the Fund's exposure to market, issuer and counterparty credit risks with respect to these financial assets is approximately their value recorded in the Statement of Assets and Liabilities, less any collateral held by the Fund.
Geographic/Asset Class Risk:  A diversified portfolio, where this is appropriate and consistent with a fund's objectives, minimizes the risk that a price change of a particular investment will have a material impact on the NAV of a fund. The investment concentrations within the Fund's portfolio are disclosed in its Schedule of Investments.
The Fund invests a significant portion of its assets in securities of issuers located in the United States. A decrease in imports or exports, changes in trade regulations, inflation and/or an economic recession in the United States may have a material adverse effect on the U.S. economy and the securities listed on U.S. exchanges. Proposed and adopted policy and legislative changes in the United States may also have a significant effect on U.S. markets generally, as well as on the value of certain securities. Governmental agencies project that the United States will continue to maintain elevated public debt levels for the foreseeable future which may constrain future economic growth. Circumstances could arise that could prevent the timely payment of interest or principal on U.S. government debt, such as reaching the legislative "debt ceiling." Such non-payment would result in substantial negative consequences for the U.S. economy and the global financial system. If U.S. relations with certain countries deteriorate, it could adversely affect issuers that rely on the United States for trade. The United States has also experienced increased internal unrest and discord. If these trends were to continue, they may have an adverse impact on the U.S. economy and the issuers in which the Fund invests.
Significant Shareholder Redemption Risk: Certain shareholders may own or manage a substantial amount of fund shares and/or hold their fund investments for a limited period of time. Large redemptions of fund shares by these shareholders may force a fund to sell portfolio securities, which may negatively impact the fund's NAV, increase the fund's brokerage costs, and/or accelerate the realization of taxable income/gains and cause the fund to make additional taxable distributions to shareholders.
8.
CAPITAL SHARE TRANSACTIONS
The number of shares sold, reinvested and redeemed corresponds to the net proceeds from the sale of shares, reinvestment of all distributions and cost of shares redeemed, respectively, since shares are sold, reinvested and redeemed at $1.00 per share.
Transactions in capital shares for each class were as follows: 
Share Class 
Year Ended
04/30/26 
Year Ended
04/30/25 
Institutional
Shares sold
98,828,266
 99,123,712
Shares issued in reinvestment of distributions
4,930,215
 5,516,888
Shares redeemed
(97,273,880)
(77,504,889)
6,484,601
27,135,711
16
2026 BlackRock Annual Financial Statements and Additional Information
Notes to Financial Statements  (continued)
 
Share Class (continued)
Year Ended
04/30/26 
Year Ended
04/30/25 
Investor A
Shares sold and automatic conversion of shares
873,633,949
 907,710,579
Shares issued in reinvestment of distributions
35,870,504
 35,764,400
Shares redeemed
(845,665,335)
(700,552,924)
63,839,118
242,922,055
Investor C
Shares sold
523,446
 1,480,710
Shares issued in reinvestment of distributions
41,519
 22,263
Shares redeemed and automatic conversion of shares
(1,085,358)
(296,370)
(520,393)
1,206,603
69,803,326
271,264,369
As of April 30, 2026, BlackRock Financial Management, Inc., an affiliate of the Fund, owned 50,000 Investor C shares of the Fund.
9.
SUBSEQUENT EVENTS
Management has evaluated the impact of all subsequent events on the Fund through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.
Notes to Financial Statements 17
Report of Independent Registered Public Accounting Firm
 
To the Shareholders of BlackRock Summit Cash Reserves Fund and the Board of Trustees of BlackRock Financial Institutions Series Trust:
Opinion on the Financial Statements and Financial Highlights
We have audited the accompanying statement of assets and liabilities of BlackRock Summit Cash Reserves Fund of BlackRock Financial Institutions Series Trust (the "Fund"), including the schedule of investments, as of April 30, 2026, the related statement of operations for the year then ended, statements of changes in net assets for each of the two years in the period then ended, financial highlights for each of the five years in the period then ended, and the related notes (collectively referred to as the "financial statements and financial highlights"). In our opinion, the financial statements and financial highlights present fairly, in all material respects, the financial position of the Fund as of April 30, 2026, and the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended, in conformity with accounting principles generally accepted in the United States of America.
Basis for Opinion
These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on the Fund's financial statements and financial highlights based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.
We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement, whether due to error or fraud. The Fund is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion.
Our audits included performing procedures to assess the risks of material misstatement of the financial statements and financial highlights, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements and financial highlights. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements and financial highlights. Our procedures included confirmation of securities owned as of April 30, 2026, by correspondence with custodians or counterparties; when replies were not received, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.
/s/ Deloitte & Touche LLP
Boston, Massachusetts
June 23, 2026
We have served as the auditor of one or more BlackRock investment companies since 1992.
18
2026 BlackRock Annual Financial Statements and Additional Information
Important Tax Information (unaudited)
 
The Fund hereby designates the following amount, or maximum amount allowable by law, of distributions from direct federal obligation interest for the fiscal year ended April 30, 2026: 
Fund Name
Federal Obligation
Interest
BlackRock Summit Cash Reserves Fund
$ 23,169,818
The law varies in each state as to whether and what percent of ordinary income dividends attributable to federal obligations is exempt from state income tax. Shareholders are advised to check with their tax advisers to determine if any portion of the dividends received is exempt from state income tax.
The Fund hereby designates the following amount, or maximum amount allowable by law, as interest income eligible to be treated as a Section 163(j) interest dividend for the fiscal year ended April 30, 2026:  
Fund Name
Interest
Dividends
BlackRock Summit Cash Reserves Fund
$ 41,069,121
The Fund hereby designates the following amount, or maximum amount allowable by law, as interest-related dividends and qualified short-term capital gains eligible for exemption from U.S. withholding tax for nonresident aliens and foreign corporations for the fiscal year ended April 30, 2026: 
Fund Name
Interest-
Related
Dividends
Qualified
Short-Term
Capital Gains
BlackRock Summit Cash Reserves Fund
$ 41,069,121
$ 30,108
Important Tax Information 19
Additional Information
 
Changes in and Disagreements with Accountants
Not applicable.
Proxy Results
Not applicable.
Remuneration Paid to Trustees, Officers, and Others
Compensation to the independent directors/trustees of the Trust is paid by the Trust, on behalf of the Fund.
General Information
Quarterly performance, shareholder reports, semi-annual and annual financial statements, current net asset value and other information regarding the Fund may be found on BlackRock's website, which can be accessed at blackrock.com. Any reference to BlackRock's website in this report is intended to allow investors public access to information regarding the Fund and does not, and is not intended to, incorporate BlackRock's website in this report.
Electronic Delivery
Shareholders can sign up for e-mail notifications of quarterly statements, annual and semi-annual shareholder reports and prospectuses by enrolling in the electronic delivery program.
To enroll in electronic delivery:
Shareholders Who Hold Accounts with Investment Advisors, Banks or Brokerages:
Please contact your financial advisor. Please note that not all investment advisors, banks or brokerages may offer this service.
Shareholders Who Hold Accounts Directly with BlackRock:
1. Access the BlackRock website at blackrock.com
2. Select "Access Your Account"
3. Next, select "eDelivery" in the "Related Resources" box and follow the sign-up instructions.
Shareholder Privileges
Account Information
Call us at (800) 441-7762 from 8:00 AM to 6:00 PM ET on any business day to get information about your account balances, recent transactions and share prices. You can also visit blackrock.com for more information.
Automatic Investment Plans
Investor class shareholders who want to invest regularly can arrange to have $50 or more automatically deducted from their checking or savings account and invested in any of the BlackRock funds.
Systematic Withdrawal Plans
Investor class shareholders can establish a systematic withdrawal plan and receive periodic payments of $50 or more from their BlackRock funds, as long as their account balance is at least $10,000.
Retirement Plans
Shareholders may make investments in conjunction with Traditional, Rollover, Roth, Coverdell, Simple IRAs, SEP IRAs and 403(b) Plans.
Fund and Service Providers
Investment Adviser
BlackRock Advisors, LLC
Wilmington, DE 19809
Accounting Agent and Custodian
State Street Bank and Trust Company
Boston, MA 02114
Transfer Agent
BNY Mellon Investment Servicing (US) Inc.
Westborough, MA 01581
Distributor
BlackRock Investments, LLC
New York, NY 10001
20
2026 BlackRock Annual Financial Statements and Additional Information
Additional Information (continued)
 
Fund and Service Providers (continued) 
Independent Registered Public Accounting Firm
Deloitte & Touche LLP
Boston, MA 02110
Legal Counsel
Ropes & Gray LLP
New York, NY 10036
 
Address of the Fund
100 Bellevue Parkway
Wilmington, DE 19809
Additional Information 21
Glossary of Terms Used in these Financial Statements
 
 
Portfolio Abbreviation 
SOFR
 Secured Overnight Financing Rate
22
2026 BlackRock Annual Financial Statements and Additional Information
THIS PAGE INTENTIONALLY LEFT BLANK. 
Want to know more?
blackrock.com | 800-441-7762
This report is intended for current holders. It is not authorized for use as an offer of sale or a solicitation of an offer to buy shares of the Fund unless preceded or accompanied by the Fund's current prospectus. You could lose money by investing in the Fund. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. An investment in the Fund is not a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund's sponsor is not required to reimburse the Fund for losses, and you should not expect that the sponsor will provide financial support to the Fund at any time, including during periods of market stress. Performance data quoted represents past performance and does not guarantee future results. Total return information assumes reinvestment of all distributions. Current performance may be higher or lower than the performance data quoted. For current month-end performance information, call (800) 626-1960. The Fund's current 7-day yield more closely reflects the current earnings of the Fund than the total returns quoted. Statements and other information herein are as dated and are subject to change.
 
 
Item 8 -

Changes in and Disagreements with Accountants for Open-End Management Investment Companies - See Item 7

Item 9 -

Proxy Disclosures for Open-End Management Investment Companies - See Item 7

Item 10 -

Remuneration Paid to Directors, Officers, and Others of Open-End Management Investment Companies - See Item 7

Item 11 -

Statement Regarding Basis for Approval of Investment Advisory Contract - Not Applicable

Item 12 -

Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies - Not Applicable

Item 13 -

Portfolio Managers of Closed-End Management Investment Companies - Not Applicable

Item 14 -

Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers - Not Applicable

Item 15 -

Submission of Matters to a Vote of Security Holders - There have been no material changes to these procedures.

Item 16 -

Controls and Procedures

(a) The registrant's principal executive and principal financial officers, or persons performing similar functions, have concluded that the registrant's disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the "1940 Act")) are effective as of a date within 90 days of the filing date of this report based on the evaluation of these controls and procedures required by Rule 30a-3(b) under the 1940 Act and Rule 13a-15(b) or 15d-15(b) under the Securities Exchange Act of 1934, as amended (the "Exchange Act").

(b) There were no changes in the registrant's internal control over financial reporting (as defined in Rule 30a-3(d) under the 1940 Act) that occurred during the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant's internal control over financial reporting.

Item 17 -

Disclosure of Securities Lending Activities for Closed-End Management Investment Companies - Not Applicable

Item 18 -

Recovery of Erroneously Awarded Compensation - Not Applicable

Item 19 -

Exhibits attached hereto

(a)(1) Code of Ethics - See Item 2

(a)(2) Any policy required by the listing standards adopted pursuant to Rule 10D-1 under the Exchange Act (17 CFR 240.10D-1) by the registered national securities exchange or registered national securities association upon which the registrant's securities are listed - Not Applicable

(a)(4) Any written solicitation to purchase securities under Rule 23c-1 - Not Applicable

(a)(5) Change in registrant's independent public accountant - Not Applicable

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

BlackRock Financial Institutions Series Trust

By:  /s/ John M. Perlowski
John M. Perlowski
Chief Executive Officer (principal executive officer) of
BlackRock Financial Institutions Series Trust

Date: June 23, 2026

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By:  /s/ John M. Perlowski

John M. Perlowski

Chief Executive Officer (principal executive officer) of

BlackRock Financial Institutions Series Trust

Date: June 23, 2026

By:  /s/ Trent Walker

Trent Walker

Chief Financial Officer (principal financial officer) of

BlackRock Financial Institutions Series Trust

Date: June 23, 2026

Blackrock Financial Institutions Series Trust published this content on July 02, 2026, and is solely responsible for the information contained herein. Distributed via EDGAR on July 02, 2026 at 15:49 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]