UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM SD

Specialized Disclosure Report

HYLIION HOLDINGS CORP.

(Exact name of the registrant as specified in its charter)

1202 BMC Drive, Suite 100 Cedar Park, TX 78613

(Address of principal executive offices) (Zip Code)

Jose Oxholm

Registrant’s Telephone Number, including area code (833) 495-4466

(Name and telephone number, including area code, of the person to contact in connection with this report.)

Check the appropriate box to indicate the rule pursuant to which this form is being filed, and provide the period to which the information in this form applies:

☒ Rule 13p-1 under the Securities Exchange Act (17 CFR 240.13p-1) for the reporting period from January 1 to December 31, 2021

SECTION 1 – CONFLICT MINERALS DISCLOSURE

Item 1.01 Conflict Minerals Disclosure and Report

Conflict Minerals Disclosure

This Specialized Disclosure Report on Form SD and the Conflict Minerals Report, filed as Exhibit 1.01 hereto, are publicly available at www.hyliion.com as well as the SEC’s EDGAR database at www.sec.gov.

Item 1.02 Exhibit

The Conflict Minerals Report required by Item 1.01 is filed as Exhibit 1.01 to this Form SD.

SECTION 2 – EXHIBITS

Item 2.01 Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused the report to be signed on its behalf by the undersigned hereunto duly authorized.

2