# EDGAR Filing Document

**Accession Number:** 0001585389
**File Stem:** 0001193125-25-137173
**Filing Date:** 2025-6
**Character Count:** 3654
**Document Hash:** 4a9bf763a2b928520b204bda1ff5e612
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-137173.hdr.sgml**: 20250606

**ACCESSION NUMBER**: 0001193125-25-137173

**CONFORMED SUBMISSION TYPE**: DEFA14A

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20250606

**DATE AS OF CHANGE**: 20250606

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** SmartStop Self Storage REIT, Inc.
- **CENTRAL INDEX KEY:** 0001585389
- **STANDARD INDUSTRIAL CLASSIFICATION:** REAL ESTATE INVESTMENT TRUSTS [6798]
- **ORGANIZATION NAME:** 05 Real Estate & Construction
- **EIN:** 461722812
- **STATE OF INCORPORATION:** MD
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** DEFA14A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-42584
- **FILM NUMBER:** 251032019

**BUSINESS ADDRESS:**
- **STREET 1:** 10 TERRACE ROAD
- **CITY:** LADERA RANCH
- **STATE:** CA
- **ZIP:** 92694
- **BUSINESS PHONE:** 949 429 6600

**MAIL ADDRESS:**
- **STREET 1:** 10 TERRACE ROAD
- **CITY:** LADERA RANCH
- **STATE:** CA
- **ZIP:** 92694

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Strategic Storage Trust II, Inc.
- **DATE OF NAME CHANGE:** 20130828

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

Check the appropriate box:

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| | |
|:---|:---|
| ☐ | Preliminary Proxy Statement |
| ☐ | **Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))** |
| ☐ | Definitive Proxy Statement |
| ☒ | Definitive Additional Materials |
| ☐ | Soliciting Material Pursuant to §240.14a-12 |
| **SmartStop Self Storage REIT, Inc.** | **SmartStop Self Storage REIT, Inc.** |
| **(Name of Registrant as Specified In Its Charter)** | **(Name of Registrant as Specified In Its Charter)** |
| **(Name of Person(s) Filing Proxy Statement, if other than the Registrant)** | **(Name of Person(s) Filing Proxy Statement, if other than the Registrant)** |
| Payment of Filing Fee (Check all boxes that apply): | Payment of Filing Fee (Check all boxes that apply): |
| ☒ | No fee required. |
| ☐ | Fee paid previously with preliminary materials. |
| ☐ | Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11. |

---

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![LOGO](g943284dsp001.jpg)

34420_R1_SSS SmartStop Self Storage REIT, Inc. ANNUAL MEETING OF STOCKHOLDERS IMPORTANT STOCKHOLDER INFORMATION Please vote promptly VOTING IS QUICK AND EASY Dear Stockholder: We recently sent you proxy materials concerning important proposals regarding your investment, which will be considered at the Annual Meeting of Stockholders on June 24, 2025. This letter was sent to you because you held shares on the record date and we have not received your vote. Your vote is critical to this process. Please vote prior to the Annual Meeting. Thank you for your prompt attention to this matter. If you have already voted, we appreciate your participation. H. Michael Schwartz Chairman and CEO SmartStop Self Storage REIT, Inc. Vote by one of these four options: Vote Online Visit the website noted on the enclosed proxy card and follow the instructions Vote by Mail Mail your signed proxy card(s) in the postage-paid envelope Vote by Phone Call the toll-free number printed on the enclosed proxy card and follow the automated instructions. Available 7 days a week 24 hours a day. Speak with a Proxy Specialist Call (844) 492-4480 with any questions. Specialists can assist with voting. Available Mon-Fri from 9 a.m. – 11 p.m. ET and Sat from noon – 6 p.m. ET