Supplemental Prospectus (Form 424B3)

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Filed pursuant to Rule 424(b)(3)

Registration No. 333-129743

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PROSPECTUS SUPPLEMENT

(To Prospectus dated November 16, 2005)

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UDR, Inc.

DIVIDEND REINVESTMENT AND STOCK PURCHASE PLAN

This prospectus supplement amends and supplements the Prospectus dated November 16, 2005, included in Form S-3 filed by UDR, Inc. (the "Company") (successor by merger to United Dominion Realty Trust, Inc.) with the Securities and Exchange Commission on November 16, 2005 (the "Prospectus"), relating to our Dividend Reinvestment and Stock Purchase Plan (the "Plan"). This prospectus supplement should be read in conjunction with the Prospectus, is qualified by reference to the Prospectus, and may not be delivered without the Prospectus. Except as expressly stated below as supplementing or superseding the information contained in the Prospectus, all other information set forth in the Prospectus is unchanged. Capitalized terms used in this prospectus supplement but not defined herein will have the same meanings as specified in the Prospectus.

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Our common stock is traded on the New York Stock Exchange under the symbol "UDR." On July 20, 2026, the last reported sale price of our common stock on the New York Stock Exchange was $39.74 per share.

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This prospectus supplement constitutes part of the Prospectus and should be retained for future reference.

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Investing in our securities involves various risks. See "Risk Factors" on page 3 of the accompanying Prospectus as well as the risk factors contained in documents we file with the Securities and Exchange Commission and which are incorporated by reference in this prospectus supplement and the accompanying Prospectus.

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Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

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The date of this prospectus supplement is July 21, 2026.

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The following information supplements and updates the information contained in the Prospectus.

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"Equiniti Trust Company, LLC ("Equiniti") administers the Plan and also serves as our transfer agent. The Plan Administrator holds certificates for shares of common stock held in your Plan account, keeps records and sends statements of your account to you. Shares purchased under the Plan are registered in the name of the Plan Administrator or its nominee, as agent, and credited to the accounts of Plan participants.

All communications regarding the Plan should be sent to:

UDR, Inc.
Dividend Reinvestment and Stock Purchase Plan
Equiniti Trust Company, LLC
P.O. Box 64856
St. Paul, MN 55164-0856

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For Certified/Overnight Mail:
Equiniti Trust Company, LLC
1110 Centre Pointe Curve, Suite 101
Mendota Heights, MN 55120-4100

General Information:
Tel: 1-800-468-9716

Tel: 651-450-4064 (outside the United States)

An automated voice response system is available 24 hours a day, 7 days a week. Customer Care Specialists are available from 7:00 a.m. to 7:00 p.m., Central Time, Monday through Friday.

Internet:

shareowneronline.com

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Available 24 hours a day, 7 days a week for access to your account information and answers for many common questions and general inquiries.

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To register for online access:

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If you are an existing, registered shareowner:

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*If you need your Authentication ID to continue, select Authentication ID and Please send my Authentication ID, then click Send ID.

Email:

Login to your account at shareowneronline.com and select Contact Us."

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"A participant may set up a monthly automatic withdrawal from a designated bank account. The request may be submitted online or by sending an Authorization Card by mail. Requests are processed and become effective as promptly as administratively possible. Once the automatic withdrawal is initiated, funds will be debited from the participant's designated bank account on or about the 25th of each month and will be

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invested in UDR, Inc. common stock on the next investment date. Changes or discontinuation of automatic withdrawals can be made online or by telephone. To be effective with respect to a particular investment date, a change request must be received by the Plan Administrator at least 15 business days prior to the investment date."

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"A participant may terminate participation in the Plan at any time by instruction to the Plan Administrator. Requests can be made by telephone or through the mail. A participant requesting termination may elect to retain UDR, Inc. shares or to sell all or a portion of the shares in the account. If a participant chooses to retain the Plan shares, they will be converted and held in book-entry DRS. Any fractional shares will be sold and a check will be sent to the participant for the proceeds. If a participant chooses to sell the Plan shares, the Plan Administrator will sell such shares at the current market value and will send the proceeds to the participant, less fees and any applicable taxes. If no election is made in the request for termination, whole Plan shares will be converted to book-entry DRS. Upon termination, any uninvested contributions will be returned to the participant. Any future dividends will be paid in cash, unless the participant rejoins the Plan.

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If the participant's request to terminate their participation in the Plan is received on or after a dividend record date, but before the dividend payable date, the participant's termination will be processed as soon as administratively possible, and a separate dividend check will be mailed to the participant.

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Beneficial owners holding their shares of common stock through a broker, bank or other nominee should consult the broker, bank or other nominee regarding procedures for withdrawal.

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If a participant moves his or her residence to a jurisdiction where shares offered pursuant to the Plan are neither registered nor exempt from registration under applicable securities laws, we may deem the participant to have terminated participation in the Plan.

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Your participation in the Plan will be terminated if you do not have at least one full share registered in your name or in your Plan account."

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"The following is a list of fees associated with participation in the Plan.

Summary

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Fees

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