Filed Pursuant to Rule 424(b)(3)
Registration No. 333-274564
Prospectus Supplement No. 28
(To Prospectus dated December 15, 2023)
ALLURION TECHNOLOGIES, INC.
Up to 56,548,268 Shares of Common Stock
This prospectus supplement no. 28 (this “Prospectus Supplement”) amends and supplements the prospectus dated December 15, 2023 (as supplemented or amended from time to time, the “Prospectus”) which forms part of our Registration Statement on Form S-1/A (Registration Statement No. 333-274564). This Prospectus Supplement is being filed to update and supplement the information included or incorporated by reference in the Prospectus with the information contained in our Current Report on Form 8-K, filed with the Securities and Exchange Commission (the “SEC”) on October 3, 2025 (the “8-K”). Accordingly, we have attached the 8-K to this Prospectus Supplement.
This Prospectus Supplement updates and supplements the information in the Prospectus and is not complete without, and may not be delivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. This Prospectus Supplement should be read in conjunction with the Prospectus, and if there is any inconsistency between the information in the Prospectus and this Prospectus Supplement, you should rely on this Prospectus Supplement.
Our common stock is listed on The New York Stock Exchange (“NYSE”) under the symbol “ALUR” and our public warrants are listed on the NYSE under the symbol “ALUR.WS”. On October 2, 2025, the last quoted sale price for shares of our common stock as reported on the NYSE was $2.07 per share, and the last quoted sale price for our public warrants as reported on the NYSE was $0.0297 per warrant.
We are an “emerging growth company” under applicable federal securities laws and will be subject to reduced public company reporting requirements.
Investing in our securities involves a high degree of risk. Before buying any securities, you should carefully read the discussion of the risks of investing in our securities in “Risk Factors” beginning on page 26 of the Prospectus.
Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued under the Prospectus or determined if the Prospectus is truthful or complete. Any representation to the contrary is a criminal offense.
The date of this Prospectus Supplement is October 3, 2025.
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): September 30, 2025
Allurion Technologies, Inc.
(Exact name of Registrant as Specified in Its Charter)
| Delaware | 001-41767 | 92-2182207 | ||
| (State or Other Jurisdiction of Incorporation) |
(Commission File Number) |
(IRS Employer Identification No.) |
| 11 Huron Drive | ||
| Natick, Massachusetts | 01760 | |
| (Address of Principal Executive Offices) | (Zip Code) |
Registrant’s Telephone Number, Including Area Code: (508) 647-4000
(Former Name or Former Address, if Changed Since Last Report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
| ☐ | Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) |
| ☐ | Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) |
| ☐ | Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) |
| ☐ | Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) |
Securities registered pursuant to Section 12(b) of the Act:
|
|
Trading |
Name of each exchange on which registered | ||
| Common stock, par value $0.0001 per share | ALUR | The New York Stock Exchange | ||
| Warrants to purchase 0.056818 shares of common stock, each at an exercise price of $202.50 per share of common stock | ALUR WS | The New York Stock Exchange |
Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).
Emerging growth company ☒
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐
Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangement of Certain Officers
On September 30, 2025, Milena Alberti-Perez, a Class III member of the board of directors (the “Board”) of Allurion Technologies, Inc. (the “Company”), notified the Company of her resignation from the Board and her role as the chairperson of the Audit Committee of the Board (the “Audit Committee”), effective September 30, 2025. Ms. Alberti-Perez’s resignation was not the result of any disagreement with management or the Board or on any matter relating to the Company’s operations, policies or practices.
Ms. Alberti-Perez resigned to focus her time in the media sector, including a new position on the board of another public company in that sector. Such resignation and resulting reduction in the size of the Board aligns with the Board’s determination that a smaller board will improve efficiency and reduce director compensation costs. Effective upon Ms. Alberti-Perez’s resignation, the size of the Board will be reduced from nine to eight. The Board is currently evaluating which of its directors will replace Ms. Alberti-Perez as chairperson of the Audit Committee.
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
| Date: October 3, 2025 | By: | /s/ Brendan M. Gibbons | ||||
| Name: Brendan M. Gibbons Title: Chief Legal Officer |