The information in this preliminary prospectus is not complete and may be changed.
Neither we nor the Selling Securityholders may sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities and is not
soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.
PRELIMINARY PROSPECTUS
SUBJECT TO COMPLETION-DATED APRIL 2, 2024
QT IMAGING HOLDINGS, INC.
Up to 49,264,364 Shares of Common Stock
Up to 12,237,565 shares of Common Stock by the Selling Securityholders
889,364 Warrants to Purchase Shares of Common Stock
This prospectus
relates to the issuance by us of an aggregate of up to 49,264,364 shares of common stock, $0.0001 par value per share, (the Common Stock) of QT Imaging Holdings, Inc. (QT Imaging Holdings or the Company),
which consists of (i) up to 23,000,000 shares of Common Stock that are issuable upon the exercise of 23,000,000 warrants, each exercisable for one share of Common Stock at a price of $[ ] per warrant (the Public
Warrants), originally issued in the initial public offering (IPO) of GigCapital5, Inc. (GigCapital5) by the holders thereof, (ii) up to 795,000 shares of Common Stock that are issuable upon the exercise of 795,000
private placement warrants, each exercisable for one share of Common Stock at a price of $[ ] per warrant (the Private Warrants), originally issued in the private placement of units closed concurrently with the IPO,
(iii) up to 94,364 shares of Common Stock that are issuable upon the exercise of 94,364 warrants, each exercisable for one share of Common Stock at a price of $[ ] per warrant issuable (together with the Private Warrants,
the Sponsors Warrants, and the Sponsors Warrants together with the Public Warrants, collectively, the Warrants), as a result of the partial conversion of the Working Capital Note (as defined below), (iv) 5,375,000
shares of Common Stock issuable pursuant to Pre-Paid Advance (as defined below) under that certain standby equity purchase agreement (the SEPA), dated November 16, 2023, by and among
GigCapital5 and YA II PN, LTD, a Cayman Islands exempt limited partnership managed by Yorkville Advisors Global, LP (Yorkville), and (v) up to 20,000,000 shares of Common Stock that we may, in our discretion, elect to issue and sell
to Yorkville, from time to time after the date of this prospectus, pursuant to the SEPA.
We will receive the proceeds from any exercise of
any Warrants for cash.
This prospectus also relates to the offer and sale from time to time by the selling securityholders named in this
prospectus (the Selling Securityholders) of up to 12,237,565 shares of Common Stock and warrants to purchase up to 889,364 shares of Common Stock, consisting of (i) 5,735,000 shares of Common Stock (the Founder Shares)
acquired by our predecessors sponsor, GigAcquisitions5, LLC, a Delaware limited liability company (the Sponsor), at an effective purchase price of $0.0043592 per share, (ii) 795,000 shares of Common Stock (the Private
Placement Shares) acquired by the Sponsor in the private placement of units concurrently with the IPO, (iii) 94,364 shares of Common Stock (Working Capital Shares) issued upon conversion in full of the working capital loans made as non-interest-bearing note (the Working Capital Note) issued to the Sponsor by our predecessor, GigCapital5, Inc. (GigCapital5), (iv) 10,000 shares of Common Stock (the Insider
Shares) issued to Interest Solutions, LLC (ICR), an affiliate of ICR, LLC, an investor relations firm providing services to GigCapital5, (v) 5,603,201 shares of Common Stock (Closing Shares) issued to former holders of
shares of common stock of QT Imaging, Inc. in connection with the Business Combination, which are parties to the Registration Rights Agreement, dated March 4, 2024, and (vi) up to 889,364 Sponsors Warrants to purchase 889,364 shares
of Common Stock. We will not receive any proceeds from the sale of shares of Common Stock or Sponsors Warrants by the Selling Securityholders pursuant to this prospectus. However, we will pay the expenses, other than underwriting discounts and
commissions and expenses incurred by the Selling Securityholders for brokerage, accounting, tax or legal services or any other expenses incurred by the Selling Securityholders in disposing of the securities, associated with the sale of securities
pursuant to this prospectus. Additional details regarding the securities to which this prospectus relates and the Selling Securityholders is set forth in this prospectus under the heading Description of Securities.
We could receive up to an aggregate of approximately $[X] million if all of the Warrants are exercised for cash. However, we will only
receive such proceeds if and when the holders of the Warrants exercise the Warrants for cash. The exercise of the Warrants, and any proceeds we may receive from any of their exercise, are highly dependent on the price of any our shares of Common
Stock and the spread between the exercise price of the Warrants and the price of our Common Stock at the time of exercise. We have outstanding (i) 23,000,000 Public Warrants to purchase 23,000,000 shares of our Common Stock, exercisable at an
exercise price of $[ ] per share, and (ii) 889,364 Sponsors Warrants to purchase 889,364 shares of our Common Stock, exercisable at an exercise price of $[ ] per share. If the market price of our
Common Stock is less than the exercise price of a holders Warrants, it is unlikely that holders will exercise their Warrants. As of , 2024, the closing price of our Common Stock was $[ ]
per share. There can be no assurance that our Warrants will be in the money prior to their expiration. Our Public Warrants under certain conditions, as described in the Warrant