Form SCHEDULE 13D 111, Inc. Filed by: Gang Yu

Sunny Bay Global Limited: c/o Vistra Corporate Services Centre, Wickhams Cay II, Road Town, Tortola, VG1110, British Virgin Islands. Junling Liu and Gang Yu: c/o 10th Floor, T1, Yuzhongxin, No. 268 Yubei Road, Pudong New Area, Shanghai, 201204, People's Republic of China.

Sunny Bay Global Limited is a company incorporated in the British Virgin Islands, wholly owned by Junling Liu, and engaged in investment holding. Junling Liu is the co-founder, co-chairman and chief executive officer of 111, Inc. Gang Yu is the co-founder and co-chairman of 111, Inc. The name, business address, present principal occupation or employment and citizenship of each executive officer and director of Sunny Bay Global Limited are set forth on Exhibit 99.4 to the filing and incorporated herein by reference.

During the last five years, none of the Reporting Persons and, to the best knowledge of each Reporting Person, any person listed on Exhibit 99.4 has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

During the last five years, none of the Reporting Persons and, to the best knowledge of each Reporting Person, any person listed on Exhibit 99.4 has been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction resulting in a judgment, decree or final order of the type described in Item 2(e).

Sunny Bay Global Limited: British Virgin Islands. Junling Liu: Australia. Gang Yu: United States of America.

This Schedule 13D is being filed by the Reporting Persons because, under the facts and circumstances described in Items 2, 4 and 5, the Reporting Persons may be deemed to be a group within the meaning of Section 13(d)(3) of the Act. This filing is not being made as a result of any particular acquisitions or dispositions of the Shares by the Reporting Persons. The Reporting Persons intend to finance the Proposed Transaction (as defined below) with equity capital in the form of rollover equity in the Issuer by the Reporting Persons and cash contribution by Huadeng Tech BioArray Ventures Ltd. The Proposed Transaction is not expected to be subject to a financing condition. The descriptions of the principal terms of the Proposal (as defined below) under Item 4 are incorporated herein by reference in their entirety.

On September 16, 2026, Gang Yu, Junling Liu, Sunny Bay Global Limited and Huadeng Tech BioArray Ventures Ltd (collectively, the Consortium) entered into a consortium agreement (the Consortium Agreement), pursuant to which the Consortium will cooperate in good faith in connection with an acquisition transaction (Proposed Transaction) with respect to the Issuer as contemplated by the Proposal (as defined below). The Consortium Agreement provides, among others, for (i) cooperation in negotiation with the Issuer with respect to the Proposed Transaction; (ii) cooperation in engaging advisors; and (iii) cooperation in entry into definitive documentation with respect to the Proposed Transaction. During the period continuing for six months after signing of the Consortium Agreement, subject to extension or early termination on the occurrence of certain termination events, members of the Consortium have agreed to work exclusively with each other with respect to the Proposed Transaction (including to vote, or cause to be voted, at shareholders' meetings against any competing transaction and in favor of the Proposed Transaction) and not to (a) make a competing proposal or (b) acquire or dispose of any securities of the Issuer. On the same date, Gang Yu, Junling Liu and Huadeng Tech BioArray Ventures Ltd submitted a non-binding proposal (the Proposal) to the Issuer's board of directors related to the proposed acquisition of all Class A ordinary shares (including Class A ordinary shares represented by ADSs) not beneficially owned by the Consortium members in a going-private transaction at a purchase price of US$0.226 per Class A ordinary share or US$4.52 per ADS. The Proposed Transaction is subject to a number of conditions, including the negotiation and execution of definitive documents and other related agreements mutually acceptable in form and substance to the Issuer and the Consortium. Neither the Issuer nor any member of the Consortium is obligated to complete the Proposed Transaction, and a binding commitment will result only from execution of definitive documents and will then be on the terms provided in such documentation. If the Proposed Transaction is completed, the Issuer's ADSs would become eligible for termination of registration pursuant to Section 12(g)(4) of the Securities Exchange Act of 1934 and would be delisted from The Nasdaq Global Market. References to the Consortium Agreement and the Proposal herein are qualified in their entirety by reference to Exhibits 99.1 and 99.2, which are incorporated herein by reference. Except as indicated above, the Reporting Persons have no plans or proposals relating to any of the actions specified in paragraphs (a) through (j) of Item 4 of Schedule 13D.

Each Reporting Person may be deemed to beneficially own an aggregate of 72,000,000 outstanding Class B ordinary shares and 2,266,328 outstanding Class A ordinary shares beneficially owned by all Reporting Persons, representing approximately 42.1% of the total outstanding share capital of the Issuer and approximately 91.4% of its aggregate voting power, because they may be deemed to constitute a group. Except as disclosed in this Schedule 13D, none of the Reporting Persons nor, to the best of their knowledge, any person listed in Exhibit 99.4 beneficially owns, or has the right to acquire, any Shares or ADSs.

The responses of each Reporting Person to Rows (7) through (13) of the cover pages of this Schedule 13D are incorporated herein by reference.

There have been no transactions in the Shares by any of the Reporting Persons during the past 60 days, other than as described herein.

Not applicable.

Not applicable.

The descriptions of the principal terms of the Proposal and the Consortium Agreement under Item 4 are incorporated herein by reference in their entirety. To the best knowledge of the Reporting Persons, except as provided herein, there are no other contracts, arrangements, understandings or relationships (legal or otherwise) among the Reporting Persons or between any Reporting Person and any other person with respect to any securities of the Issuer, including joint ventures, loan or option arrangements, puts or calls, guarantees of profits, divisions of profits or loss, the giving or withholding of proxies, or any pledge or contingency the occurrence of which would give another person voting power over the securities of the Issuer.

Exhibit 99.1: Consortium Agreement among Gang Yu, Junling Liu, Sunny Bay Global Limited and Huadeng Tech BioArray Ventures Ltd, dated September 16, 2026. Exhibit 99.2: Proposal Letter from Gang Yu, Junling Liu and Huadeng Tech BioArray Ventures Ltd to the Board of Directors of 111, Inc., dated September 16, 2026. Exhibit 99.3: Joint Filing Agreement among the Reporting Persons, dated September 17, 2026. Exhibit 99.4: Executive officer and director of Sunny Bay Global Limited.