CITIC Securities Company Limited's Listing Sponsorship Letter Regarding STO Express Co., Ltd.'s 2026 Issuance of Convertible Corporate Bonds to Unspecified Targets

CITIC Securities Company Limited Regarding STO Express Co., Ltd. 2026 Issuance of Convertible Corporate Bonds to Unspecified Targets Listing Sponsorship Letter

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North Tower, Excellence Times Plaza (Phase II), No. 8 Center 3rd Road, Futian District, Shenzhen, Guangdong Province

July 2026

Statement

CITIC Securities Company Limited (hereinafter "CITIC Securities" or "Sponsor") has been engaged by STO Express Co., Ltd. (hereinafter "STO Express," "Issuer," or "Company") to act as the sponsor for the 2026 issuance of convertible corporate bonds to unspecified targets.

The Sponsor and its designated sponsor representatives have acted in accordance with the Company Law of the People's Republic of China, the Securities Law of the People's Republic of China, and other relevant laws, regulations, and rules stipulated by the China Securities Regulatory Commission and the Shenzhen Stock Exchange. We have acted with honesty, integrity, and due diligence, strictly following established business rules and industry standards to issue this listing sponsorship letter, and we guarantee that the documents provided are true, accurate, and complete. If the documents prepared or issued by the Sponsor for this issuance contain false records, misleading statements, or major omissions that cause losses to investors, the Sponsor will compensate investors for their losses in accordance with the law.

In this listing sponsorship letter, unless the context otherwise requires, terms used herein have the same meanings as those defined in the "STO Express Co., Ltd. 2026 Issuance of Convertible Corporate Bonds to Unspecified Targets Prospectus."

Table of Contents

Statement 1

Table of Contents 2

Section 1 Basic Information on the Securities Issuance 3

I. Basic Information of the Issuer 3

II. Issuance Information of the Securities Applied for Listing 14

III. Decision-making Procedures for this Issuance 23

IV. Information on Sponsor Representatives, Project Coordinators, and Other Project Team Members 24

Section 2 Affiliated Relationships Between the Sponsor and the Issuer 25

I. Shareholding of the Sponsor or its Controlling Shareholders, Actual Controllers, or Important Affiliates in the Issuer or its Controlling Shareholders or Important Affiliates 25

II. Shareholding of the Issuer or its Controlling Shareholders or Important Affiliates in the Sponsor or its Controlling Shareholders, Actual Controllers, or Important Affiliates 25

III. Interests of the Sponsor's Representatives and their Spouses, Directors, Supervisors, and Senior Management in the Issuer, and their Positions Held in the Issuer 25

IV. Provision of Guarantees or Financing Between the Sponsor's Controlling Shareholders, Actual Controllers, or Important Affiliates and the Issuer's Controlling Shareholders, Actual Controllers, or Important Affiliates 25

V. Other Affiliated Relationships Between the Sponsor and the Issuer 26

Section 3 Sponsor's Commitments 27

Section 4 Work Arrangements for the Sponsor's Continuous Supervision of the Issuer 28

Section 5 Other Matters the Sponsor Deems Necessary to Explain 29

Section 6 Sponsor's Recommendation Conclusion for this Listing 30

Section 1 Basic Information on the Securities Issuance

I. Basic Information of the Issuer

(I) Issuer Overview