| Item 1. | Security and Issuer |
| (a) | Title of Class of Securities:
Class A Common Stock, par value $0.0001 per share |
| (b) | Name of Issuer:
BOOST RUN INC. |
| (c) | Address of Issuer's Principal Executive Offices:
5 Revere Drive, Suite 200, Northbrook,
ILLINOIS
, 60062. |
| Item 2. | Identity and Background |
|
| (a) | Andrew Karos |
| (b) | The principal business address of Andrew Karos is c/o Boost Run Inc., 5 Revere Drive, Suite 200 Northbrook, IL 60062 |
| (c) | Andrew Karos is the Chief Executive Officer and a member of the Board of Directors of the Issuer. |
| (d) | No |
| (e) | No |
| (f) | United States of America |
| Item 3. | Source and Amount of Funds or Other Consideration |
| | The shares of common stock reported herein as being beneficially owned by the Reporting Person were issued following the completion of the business combination on May 8, 2026 (the "Closing Date"), pursuant to that certain Business Combination Agreement dated as of September 15, 2025, as amended by Amendment No. 1 to the Business Combination Agreement, dated January 13, 2026 (the "Business Combination Agreement" and together with the other agreements and transaction contemplated by the Business Combination Agreement, the "Business Combination"), between Boost Run Inc., a Delaware corporation (the "Company"), Willow Lane Acquisition Corp., a Cayman Islands exempted company ("SPAC"), Benchmark Merger Sub I Inc., a Delaware corporation and wholly-owned subsidiary of the Company ("SPAC Merger Sub"), Boost Run Holdings, LLC, a Delaware limited liability company ("Legacy Boost Run"), Benchmark Merger Sub II LLC, a Delaware limited liability company and wholly-owned subsidiary of the Company ("Company Merger Sub"), Andrew Karos, solely in his capacity as the representative of the holders of Legacy Boost Run's issued and outstanding membership interests, and George Peng, solely in his capacity as the representative of SPAC shareholders.
On the Closing Date, SPAC Merger Sub merged with and into SPAC, with SPAC surviving as a wholly-owned subsidiary of the Company (the "SPAC Merger"). Simultaneously with the SPAC Merger, Company Merger Sub merged with and into Legay Boost Run, with, pursuant to the Certificate of Merger, the surviving entity continuing as Boost Run Services, LLC and a wholly-owned subsidiary of the Company. As a result of the Business Combination, SPAC and Boost Run became wholly-owned subsidiaries of the Company and the Company became a publicly traded company.
At the effective time of the Business Combination, stock consideration was issued to the then current holders of stock in Legacy Boost Run in the form of common stock of the Company. |
| Item 4. | Purpose of Transaction |
| | The information regarding the Business Combination set forth in Item 3 above is incorporated into this Item 4 by reference.
Reporting Person serves a member of the Board of Directors and as the Chief Executive Officer of the Issuer, and, in such capacity, may have influence over the corporate activities of the Issuer, including activities which may relate to items described in subparagraphs (a) through (j) of Item 4 of Schedule 13D.
Except as described in this Schedule 13D, the Reporting Person does not have any present plans or proposals that relate to or would result in any of the actions described in subparagraphs (a) through (j) of Item 4 of Schedule 13D, although, subject to the agreements described herein, the Reporting Person, at any time, and from time to time, may review, reconsider and change his position and/or change his purpose and/or develop such plans and may seek to influence management of the Issuer or the Board with respect to the business and affairs of the Issuer and may from time to time consider pursuing or proposing such matters with advisors, the Issuer, or other persons. |
| Item 5. | Interest in Securities of the Issuer |
| (a) | See responses to Item 13 on the cover page.
Consists of 29,533,018 shares of Class B Common Stock. Each share of Class B Common Stock is convertible into one share of Class A Common Stock. Shares of Class B common stock held by the Reporting Person will automatically convert into an equal number of shares of Class A common stock upon (i) any sale, assignment, transfer or other disposition of such shares, other than certain permitted transfers, (ii) his cessation as an executive officer or director of the Company, or (iii) the date on which he ceases to beneficially own at least 40% of the shares of Class B common stock he held immediately following the closing, in each case subject to specified exceptions. Soley for purposes of this line item, the aggregate number of shares of Class B Common Stock beneficially owned by the Reporting Person is treated as converted into shares of Class A Common Stock. |
| (b) | See responses to Items 7, 8, 9 and 10 on the cover page. |
| (c) | Except as set forth in this Schedule 13D, the Reporting Person has not, to the best of his knowledge, engaged in any transaction with respect to the common stock during the sixty days prior to the date of filing this Schedule 13D. |
| (d) | Except as described in Item 3, no person other than the Reporting Person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the shares of the common stock of the issuer beneficially owned by the Reporting Person as reported in this Schedule 13D. |
| (e) | Not applicable. |
| Item 6. | Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer |
| | Lock-Up Agreement
In connection with the Business Combination, on September 15, 2025, the Company entered into Lock-Up Agreements (the "Lock-Up Agreements") with certain stockholders of Legacy Boost Run, pursuant to which each of the parties to the Lock-Up Agreements agreed not to effect any sale or distribution of any equity securities of Pubco held by any of them during the lock-up period set forth therein.
The foregoing description of the Lock-Up Agreement is qualified in its entirety by reference to the full text of the agreement, a copy of which is attached as Exhibit 99.1 to this Schedule 13D and is incorporated herein by reference.
Registration Rights Agreement
In connection with the Business Combination, on the Closing Date, the Company entered into an Amended and Restated Registration Rights Agreement (the "Registration Rights Agreement") pursuant to which it agreed to register for resale shares of the Issuer's Common Stock and other securities held by the certain stockholders, subject to the terms and conditions described therein.
The foregoing description of the Registration Rights Agreement is qualified in its entirety by reference to the full text of the agreement, a copy of which is attached as Exhibit 99.2 to this Schedule 13D and is incorporated herein by reference. |
| Item 7. | Material to be Filed as Exhibits. |
| | 99.1 - Lock-Up Agreement (Incorporated by reference to Exhibit 10.2 to Willow Lane Acquisition Corp.'s Current Report on Form 8-K, filed with the Securities and Exchange Commission on September 19, 2025).
99.2 - Registration Rights Agreement, dated May 8, 2026, by and among the Company and the parties thereto (Incorporated by reference to Exhibit 10.2 to Boost Run Inc.'s Current Report on Form 8-K, filed with the Securities and Exchange Commission on May 14, 2026). |
