Hyliion Holdings Corp.

We are furnishing proxy materials to some of our stockholders via the Internet by mailing a Notice of Internet Availability of Proxy Materials, instead of mailing or e-mailing copies of those materials. The Notice of Internet Availability of Proxy Materials directs stockholders to a website where they can access our proxy materials, including our proxy statement and our annual report, and view instructions on how to vote via the Internet, mobile device, or by telephone. If you received a Notice of Internet Availability of Proxy Materials and would prefer to receive a paper copy of our proxy materials, please follow the instructions included in the Notice of Internet Availability of Proxy Materials. We are also providing the option for stockholders to elect to receive our proxy materials via e-mail in the future, and if you make this election, you will receive access to those materials electronically unless you elect otherwise. We encourage you to register to receive all future stockholder communications electronically, instead of in print. This means that access to the annual report, proxy statement, and other correspondence will be delivered to you via e-mail.