Exhibit 99.1

Consent of KeyBanc Capital Markets Inc.

We hereby consent to (i) the inclusion of our opinion letter dated July 13, 2026, to the Special Committee of the Board of Directors and the Board of Directors of Strategic Storage Growth Trust III, Inc. (“SSGT III”), as Annex B to the Proxy Statement and Prospectus of SSGT III and Strategic Storage Trust VI, Inc. (“SST VI”), which forms part of the Registration Statement on Form S-4 of SST VI filed with the Securities and Exchange Commission (the “Commission”) as of the date hereof (the “Registration Statement”), and (ii) the references to such opinion and to our name in the Registration Statement under the subheadings “Background of the Merger,” “SSGT III’s Reasons for the Merger and Recommendation of the SSGT III Board,” “Opinion of the SSGT III Special Committee’s Financial Advisor,” “Summary of Financial Analyses of the SSGT III Special Committee’s Financial Advisor,” and “Certain SST VI and SSGT III Unaudited Financial Projections.”

In giving such consent, we do not admit that we come within the category of persons whose consent is required under Section 7 of the Securities Act of 1933, as amended (the “Act”), or the rules and regulations of the Commission thereunder, nor do we hereby admit that we are experts with respect to any part of the Registration Statement within the meaning of the term “experts” as used in the Act, or the rules and regulations of the Commission thereunder.

 

Date: August 27, 2026