Prospectus by Investment Company (Form 497)

MassMutual Ascend Life Insurance Company

Index Achiever Advisory Annuity

Individual Index-linked Modified Single Premium Deferred Annuity

Supplement Dated June 30, 2026

To the Prospectus and Updating Summary Prospectus Dated May 1, 2026

This supplement is intended to update certain information in the prospectus and updating summary prospectus for the Index Achiever Advisory index-linked annuities ("Contracts"). All other provisions outlined in your prospectus and updating summary prospectus remain unchanged. Unless otherwise indicated, terms used in this supplement have the same meaning as in your Contract prospectus and updating summary prospectus.

CONTRACT FEATURES

Effective the date of this supplement, the description of the feature on Page 11 of the prospectus is deleted and replaced with the following:

A Performance Lock allows you to lock in the Daily Value Percentage of an eligible Indexed Strategy for the remainder of a Term. You may make a Performance Lock election for any Term or Terms of the S&P 500 Indexed Strategies (excluding the three Trigger Strategies), the First Trust Barclays Edge Indexed Strategies, and the Russell 2000 Indexed Strategies. A Performance Lock election is not available for Contracts issued in Missouri with a Contract Effective Date before May 21, 2025.

INDEXED STRATEGY VALUE AFTER PERFORMANCE LOCK ELECTION

Effective the date of this supplement, the first paragraph under the heading on Page 51 of the prospectus is deleted and replaced with the following:

Performance Lock is an election to lock in the Daily Value Percentage for the remainder of a Term of an Indexed Strategy. You can make a Performance Lock election for each Term of an S&P 500 Strategy (excluding the three Trigger Strategies), a First Trust Barclays Edge Strategy, and a Russell 2000 Strategy. A Performance Lock election is not available for Contracts issued in Missouri with a Contract Effective Date before May 21, 2025. Only one Performance Lock election may be made for a given Term of a Strategy.

INDEXED STRATEGY AVAILABILITY IN CALIFORNIA

The following four Combination Strategies are available for Contracts issued in with a Contract Effective Date on or after January 7, 2026, but only for Terms beginning after July 20, 2026:

S&P 500 10% Buffer with Upside Participation Rate and Cap Indexed Strategy

S&P 500 20% Buffer with Upside Participation Rate and Cap Indexed Strategy

Russell 2000 10% Buffer with Upside Participation Rate and Cap Indexed Strategy

Russell 2000 20% Buffer with Upside Participation Rate and Cap Indexed Strategy

The following four Combination Strategies are available for Contracts issued in with a Contract Effective Date on or after July 21, 2026:

S&P 500 10% Buffer with Upside Participation Rate and Cap Indexed Strategy

S&P 500 20% Buffer with Upside Participation Rate and Cap Indexed Strategy

Russell 2000 10% Buffer with Upside Participation Rate and Cap Indexed Strategy

Russell 2000 20% Buffer with Upside Participation Rate and Cap Indexed Strategy

The following six Indexed Strategies will continue to be available for Contracts issued in with a Contract Effective Date before September 7, 2026:

S&P 500 10% Buffer with Upside Participation Rate Indexed Strategy

S&P 500 20% Buffer with Upside Participation Rate Indexed Strategy

S&P 500 10% Buffer with Upside Participation Rate Indexed Strategy

S&P 500 20% Buffer with Upside Participation Rate Indexed Strategy

Russell 2000 10% Buffer with Upside Participation Rate Indexed Strategy

Russell 2000 20% Buffer with Upside Participation Rate Indexed Strategy

The following two Indexed Strategies will continue to be available for Contracts issued in with a Contract Effective Date on or after May 21, 2025, and before September 7, 2026:

Russell 2000 10% Buffer with Upside Participation Rate Indexed Strategy

Russell 2000 20% Buffer with Upside Participation Rate Indexed Strategy

APPENDIX A: INVESTMENT OPTIONS AVAILABLE UNDER THE CONTRACT

Effective as of the date of this supplement, ("Appendix A") in the prospectus and the updating summary prospectus is deleted and replaced with the following Appendix A to reflect changes to the footnotes addressing the availability of certain strategies in .

APPENDIX A: INVESTMENT OPTIONS AVAILABLE UNDER THE CONTRACT

The following is a list of Indexed Strategies currently available under the Contract. We may change the features of the Indexed Strategies listed below (including the Index and the current limits on Index gains and losses), offer new Indexed Strategies, and terminate existing Indexed Strategies. We will provide you with written notice before making any changes other than changes to current limits on Index gains. Information about current limits on Index gains is available at . For additional information about the features of the Indexed Strategies, please see the Indexed Strategies section in the prospectus. The practical availability of investment options at the time of sale may vary depending on the broker-dealer through which the Contract is sold. See Appendix D - Financial Intermediary Variations in the prospectus.

Note: If amounts are removed from an Indexed Strategy before the end of its Term, we will apply a Daily Value Percentage adjustment. This may result in a significant reduction in your Strategy value that could exceed any protection from Index loss that would be in place if you held the Indexed Strategy until the end of the Term. You may not be able to invest in certain Indexed Strategies, as noted below.

The following eight additional Indexed Strategies are available for Contracts with a Contract Effective Date before February 21, 2026. For Contracts issued in they are available for Contracts issued with a Contract Effective Date before September 7, 2026.

The is a "price return index," not a "total return index," and therefore does not reflect dividends paid on the securities composing the Index. This will reduce the Index return and cause the Index to underperform a direct investment in the securities composing the Index.

The deducts fees and costs when calculating Index performance. This will reduce the ETF's return and cause the ETF to underperform a direct investment in the securities composing the ETF.

The deducts fees and costs when calculating Index performance. This will reduce the ETF's return and cause the ETF to underperform a direct investment in the securities composing the ETF.

The deducts fees and costs when calculating Index performance. This will reduce the ETF's return and cause the ETF to underperform a direct investment in gold bullion.

The is an "excess return index" that subtracts a risk-free interest rate from the price and dividend return of the securities. It also deducts fees and costs when calculating Index performance. This will reduce the Index's return and cause the Index to underperform a direct investment in the securities composing the Index.

The is a "price return index," not a "total return index," and therefore does not reflect dividends paid on the securities composing the Index. This will reduce the Index return and cause the Index to underperform a direct investment in the securities composing the Index.

Possible Changes in Indexed Strategies.

The S&P 500 Floor with Cap Indexed Strategy will always be available. At the end of a Term, we may stop offering any other Indexed Strategy. Consequently, any other Indexed Strategy listed above may not be available after the end of the initial Term. We have the right to replace the Index associated with an Indexed Strategy under certain circumstances.

In the future, we may offer new Indexed Strategies. Any new Buffer Strategy will offer protection against loss at least equal to a 5% Buffer. Any new Floor Strategy will offer protection against loss at least equal to a Floor. Any new Downside Participation Rate Strategy will offer protection against loss at least equal to a 75% Downside Participation Rate.

Positive return factors can change from one Term to the next, subject to the following minimum rates: A Cap will never be lower than 1%, an Upside Participation Rate will never be lower than 5%, and a Trigger Rate will never be lower than 1%. Indexed Strategies that may be available in the future may earn a return that is lower than the return your investments would have earned if they had been invested in the other Indexed Strategies that are currently available. In addition, any reduction in the available number of Indexed Strategies may reduce your opportunity to increase your Contract value.

The following lists the Fixed Account Option currently available under the Contract. We may change the features of the Fixed Account Option listed below, offer new Fixed Account Options, and terminate existing Fixed Account Options. We will provide you with written notice before doing so.

Theinterest rate for the Declared Rate Strategy Rate will never be less than the guaranteed minimum interest rate from 0.15% to 3.0% set out in the Declared Rate Strategy endorsement included in your Contract. The guaranteed minimum interest rate set out in the endorsement will never be less than the minimum interest rate required for fixed annuity contracts on the Contract Effective Date under the Standard Nonforfeiture Law of the state in which your Contract is issued. For additional information on the Declared Rate Strategy, see the Declared Rate Strategy section in the prospectus.

If you have any questions about this supplement, please call or contact your registered representative.

Please retain this supplement for future reference.