UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934 (Amendment No.     )

Filed by the Registrant  x

Filed by a Party other than the Registrant  ¨

Check the appropriate box:

¨ Preliminary Proxy Statement

¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

¨ Definitive Proxy Statement

x Definitive Additional Materials

¨ Soliciting Material under §240.14a-12

Sunstone Hotel Investors, Inc.

(Name of Registrant as Specified in Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

x No fee required.

¨ Fee paid previously with preliminary materials.

¨ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a6(i)(1) and 0-11.

Your Vote Counts! SUNSTONE HOTEL INVESTORS, INC. 200 SPECTRUM CENTER DRIVE 21ST FLOOR IRVINE, CA 92618 SUNSTONE HOTEL INVESTORS, INC. 2022 Annual Meeting Vote by April 27, 2022 11:59 PM ET You invested in SUNSTONE HOTEL INVESTORS, INC. and it’s time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy material for the stockholder meeting to be held on April 28, 2022. Get informed before you vote View the Notice of Meeting and Proxy Statement online OR you can receive a free paper or email copy of the material(s) by requesting prior to April 14, 2022. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. Vote in Person at the Meeting* April 28, 2022 9:30 AM ET Boston Park Plaza 50 Park Plaza Boston, MA 02116 *Please check the meeting materials for any special requirements for meeting attendance. At the meeting, you will need to request a ballot to vote these shares. Smartphone users Point your camera here and vote without entering a control number V1.1 For complete information and to vote, visit www.ProxyVote.com Control # D69330-P67125

THIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters. Vote at www.ProxyVote.com Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Sign up for E-delivery”. Voting Items Board Recommends D69331-P67125 1. Election of the following seven nominees to serve as directors until the next Annual Meeting and until their successors are elected and qualified: Nominees: 1b. Andrew Batinovich 1c. Monica S. Digilio 1a. W. Blake Baird 1d. Kristina M. Leslie 1e. Murray J. McCabe 1f. Verett Mims 1g. Douglas M. Pasquale 2. Ratification of the Audit Committee’s appointment of Ernst & Young LLP to act as the independent registered public accounting firm for the fiscal year ending December 31, 2022. 3. Advisory vote to approve the compensation of Sunstone’s named executive officers, as set forth in Sunstone’s Proxy Statement for the 2022 Annual Meeting. 4. Approval of the Sunstone Hotel Investors, Inc. and Sunstone Hotel Partnership, LLC 2022 Incentive Award Plan. For For For For For For For For For For NOTE: Transaction of such other business as may be properly brought before the Annual Meeting or any adjournment or postponement thereof. THE PROXY, WHEN PROPERLY EXECUTED, WILL BE VOTED IN THE MANNER DIRECTED. IF NO DIRECTION IS MADE, THE PROXY WILL BE VOTED “FOR” EACH OF THE NOMINEES IN PROPOSAL 1 AND “FOR” PROPOSALS 2, 3 AND 4. THE PROXY ALSO CONFERS DISCRETIONARY AUTHORITY ON THE PROXY HOLDERS TO VOTE AS TO ANY OTHER MATTER THAT IS PROPERLY BROUGHT BEFORE THE ANNUAL MEETING THAT THE BOARD OF DIRECTORS DID NOT HAVE NOTICE OF PRIOR TO MARCH 17, 2022.