Company: FTCI
Filing Date: 2025-05-16
Form Type: S-3/A
Source: 0001193125-25-121719
Chunk: 63

Company: FTC Solar, Inc.
Filing Date: 2025-05-16
Form: S-3/A
Chunk 63
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 exercisable, having a weighted average exercise price of $22.13 per share); and |

| • |     | 1,593,926 shares of common stock issuable upon vesting of restricted stock units, having an estimated grant date 
 fair value of $4.91 per share.                                                                                   |

S-16

DESCRIPTION OF THE SECURITIES THAT WE ARE OFFERING

We are offering up to 3,354,947 shares of common stock at an assumed offering price of $4.10 per share, which was the closing price of our
common stock on Nasdaq on May 14, 2025, for aggregate gross proceeds of $13,755,287. The following description of our shares of common stock summarizes the material terms and provisions thereof.

Common Stock

For a description of the
rights associated with the common stock, see “Description of Capital Stock” in the accompanying base prospectus. Our common stock is listed on the Nasdaq Capital Market under the symbol “FTCI.” The transfer agent for the
common stock is Continental Stock Transfer & Trust.

S-17

PLAN OF DISTRIBUTION

We have entered into the Sales Agreement, dated as of May 1, 2025, under which we may offer and sell shares of our common stock from time to
time through Wainwright as the sales agent. Pursuant to this prospectus supplement and the accompanying base prospectus, from time to time we may offer and sell shares of our common stock having an aggregate gross sales price of up to $13,755,287.

The Sales Agreement provides that sales of our common stock, if any, under this prospectus supplement and the accompanying base
prospectus may be made in sales deemed to an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act, including sales made directly on or through the Nasdaq Capital Market, the existing trading market for
our common stock, or any other existing trading market in the United States for our common stock, sales made to or through a market maker other than on an exchange or otherwise, directly to the Manager as principal, in negotiated transactions at
market prices prevailing at the time of sale or at prices related to such prevailing market prices, and/or in any other method permitted by law.

Wainwright will offer shares of our common stock at prevailing market prices subject to the terms and conditions of the Sales Agreement as
agreed upon by us and Wainwright. We will designate the