Form DEFA14A AIM INVESTMENT SECURITIE

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

Filed by the Registrant ☒       Filed by a Party other than the Registrant ☐

Check the appropriate box:

AIM INVESTMENT SECURITIES FUNDS (INVESCO INVESTMENT SECURITIES FUNDS)

(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):

QUESTIONS & ANSWERS:

Invesco Real Estate Fund

We encourage you to read the proxy statement in full; however, the following represent some typical questions that shareholders may have regarding the proxy statement.

HOW DO I VOTE?

Voting may take place in the following ways:

WHAT IS THE PROPOSAL BEING PRESENTED AT THE SHAREHOLDER MEETING AND WHAT AM I BEING ASKED TO VOTE ON?

HOW DOES THE BOARD RECOMMEND THAT I VOTE?

The Board unanimously recommends that you vote FOR the proposal.

WHY SHOULD I VOTE?

Every vote is important – this means your vote too. If shareholders fail to vote their proxies, the Fund may not receive enough votes to go forward with the July 10, 2025 shareholder meeting. If this happens, additional solicitations may have to be made to obtain a quorum, or proxies may have to be resent to shareholders.

WHO HAVE WE CONTRACTED FOR THE SERVICES OF A PROXY SOLICITOR?

We have hired Sodali Fund Services as the Fund’s proxy solicitor. If we do not receive your vote after a reasonable amount of time, you may receive a telephone call and other solicitations from them reminding you to vote your shares.

WILL MY VOTE BE CONFIDENTIAL USING THE ONLINE PROXY VOTING SYSTEM?

The Web proxy voting system offered by the www.proxyvotenow.com maintains security features designed to protect the confidentiality of your vote. These security features include:

HOW DO I SIGN THE PROXY CARD AND/OR VOTING INSTRUCTION CARD?

The following general rules for signing proxy cards and/or voting instruction cards could help you avoid the time and expense involved in validating your vote if you fail to sign your proxy card and/or voting instruction card properly.

Individual and Joint Accounts: Shareholders and joint owners should sign exactly as their name appears in the account registration shown on the proxy card and/or voting instruction card. If shares are held jointly, one or more owners should sign personally.

All Other Accounts: The capacity of the individual signing the proxy card and/or voting instruction card (for example, “trustee”) should be indicated, along with the individual’s signature and full title. If a corporation, limited liability company, or partnership, please sign the full entity name and indicate the signer’s position with the entity.

WHAT IS THE DEADLINE FOR VOTING?

All votes must be received before or at the shareholder meeting, which will be held on July 10, 2025 at 1:00 p.m. Central Time.

WHERE CAN I FIND MORE INFORMATION CONCERNING THE PROPOSAL?

Further details about the proposal can be found in the proxy statement.

Thank you for calling Invesco.

If you have questions regarding the Special Meeting of Shareholders for Invesco Active U.S. Real Estate ETF taking place on July 10, 2025 in Downers Grove, Illinois, Press 1.

If you have questions regarding the Special Meeting of Shareholders for Invesco Real Estate Fund taking place on July 10, 2025 in Houston, Texas, Press 2.

If you plan to attend the Special Meeting of Shareholders of Invesco Active U.S. Real Estate ETF, Press 3.

If you plan to attend the Special Meeting of Shareholders of Invesco Real Estate Fund, Press 4.

Invesco Invesco Real Estate Fund important Dates Welcome to the Proxy Voting System for Invesco Real Estate Fund Meeting Date: 07/10/2025 Your electronic proxy vote has the same validity as a properly executed proxy card returned by mail. To access the voting system, enter the Control Number provided on your proxy card or email notification, and click—CONTINUE. Voting Starts: 05/08/2025 Voting Ends: Enter the Control Number found on your proxy card: 1............... II Continue 1 07/10/2025 11 Accessing this site from a mobile device? Click here for a mobile-friendly version. © 2305-2025 All Rights Reserved. Terms and Conditions | Privacy Notice

4^lnvesco Invesco Real Estate Fund Important Dates Select a Voting Option Record Date: 04/21/2025 Meeting Date: INVESCO REAL ESTATE FUND (the “Fund”) 07/10/2025 (i) A SERIES OF AIM INVESTMENT SECURITIES FUNDS (INVESCO INVESTMENT SECURITIES FUNDS) (the “Trust”) PROXY FOR THE SPECIAL MEETING OF SHAREHOLDERS TO BE HELD JULY 10, 2025 Voting Starts: THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF TRUSTEES 05/08/2025 The undersigned shareholder of the Fund hereby appoints Melanie Ringold, Glenn Brightman, Adrien Deberghes. Voting Ends: Taylor Edwards and Adam Henkel, and any one of them separately, proxies with lull power of substitution in each, 07/10/2025 and hereby authorizes them to represent and to vote, as designated on the reverse of this proxy card, at the Special Meeting of Shareholders to be held at 11 Greenway Plaza. Houston, Texas 77046-1173 on July 10, 2025, at 1:00 p.m. Central Time, and at any adjournment(s), postponement(s) or delay(s) thereof, all of the Shares of the Fund which the undersigned would be entitled to vote if personally present. Please refer to the Proxy Statement for a discussion of this matter, including instructions related to the meeting attendance. THIS PROXY CARD, WHEN PROPERLY EXECUTED, WILL BE VOTED IN THE MANNER DIRECTED HEREIN. Logoff IF THIS PROXY CARD IS SIGNED AND RETURNED BUT NO CHOICE IS INDICATED, THE SHARES WILL BE VOTED “FOR” THE PROPOSAL, AS RECOMMENDED BY THE BOARD, AT THE DISCRETION OF THE PROXIES. PROXIES ARE AUTHORIZED TO VOTE, IN THEIR DISCRETION, UPON SUCH OTHER BUSINESS AS MAY PROPERLY COME BEFORE THE MEETING AND IN ACCORDANCE WITH THE VOTING STANDARDS SET FORTH IN THE PROXY STATEMENT WITH RESPECT TO ANY ADJOURNMENT OR POSTPONEMENT OF THE MEETING.. Please choose from one of the following two voting options.

4^lnvesco Invesco Real Estate Fund Important Dates Record Date: 04/21/2025 © Please Make Your Proxy Voting Selection(s) Below Previous Vote On File: None Vote by 07/10/2025. You may change your vote at any time until this deadline. Meeting Date: 07/10/2025 © ltem(s) not marked with a voting response will be voted as the Board of Trustees recommends. Your control number 10316999990020 Voting Starts: 05/08/2025 voting starts: 07/10/2025 Proposal 1 BOARD RECOMMENDATION: FOR To approve changing the Fund’s sub-classification from “diversified” to “non-diversified” and the elimination of the related fundamental FOR AGAINST ABSTAIN investment restriction. Log off | Proceed | © 2005-2025 All Rights Reserved. Terms and Conditions | Privacy Notice

Invesco Real Estate FUND review Voting Summary And Submit your vote Record Date: 04/21/2025 Meeting Date: 07/10/2025, Please review your selection Below to register your vote click the submit vote Button at the buttom your vote will not be filed untill you have clicked this button, Proposal 1to approve changing the fund’s sub classification from diversified to non- diversified and for the elemination of the related fundamental investment restriction.Submit Vote Modify vote. Logg Off,

Invesco Real Estate Fund Telephone Script

2025 Special Meeting