UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION QT Imaging Holdings, Inc. (f/k/a GigCapital5, Inc.) (the Company ) is providing the following unaudited pro forma condensed combined financial information to a

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

QT Imaging Holdings, Inc. (f/k/a GigCapital5, Inc.) (the Company ) is providing the following unaudited pro forma condensed

combined financial information to aid you in your analysis of the financial aspects of the business combination between GigCapital5, Inc. and QT Imaging, Inc., which was consummated on March 4, 2024. The historical financial information of QT

Imaging, Inc. was derived from the unaudited financial statements for the nine months ended September 30, 2023.

The historical financial

information of GigCapital5, Inc. was derived from the unaudited financial statements for the nine months ended September 30, 2023. This information should be read together with QT Imaging, Inc. s and GigCapital5 Inc. s financial statements

Description of the Transaction

On March 4, 2024, GigCapital5, Inc. and its wholly owned subsidiary, QTI Merger Sub, Inc., entered into a Business Combination Agreement

with QT Imaging, Inc. Following the approval at the special meeting of the stockholders of GigCapital5, Inc. held on February 20, 2024, and pursuant to and in accordance with the terms of the Business Combination Agreement, QTI Merger Sub, Inc.

merged with and into QT Imaging, Inc. with QT Imaging Holdings Inc. surviving the merger. Upon the consummation of the merger, GigCapital5, Inc. changed its name to QT Imaging Holdings, Inc.

Subject to and in accordance with the terms of the Business Combination Agreement and customary adjustments, at the effective time of the

merger, each share of QT Imaging, Inc. capital stock issued and outstanding immediately prior to the effective time of the merger (including shares issued upon the exercise or conversion of QT Imaging Options, QT Imaging Warrants and QT Imaging

Convertible Notes but excluding each share of QT Imaging Common Stock held in the treasury of QT Imaging which will be cancelled without any conversion of such shares of QT Imaging Common Stock held in the treasury and dissenting shares) will

be automatically cancelled and converted into (A) a number of shares of GigCapital5 Common Stock equal to the Exchange Ratio of the quotient of (i) the Aggregate Closing Merger Consideration divided by (ii) the QT Imaging Fully

Diluted Capital Stock and (B) the contingent right to receive a portion of additional shares of GigCapital5 Common Stock based on the performance of the Combined Company if certain requirements are achieved in accordance with the terms of the

Business Combination Agreement, if, as and when payable.

Accounting for the Transactions

The business combination is accounted for as a reverse recapitalization in accordance with U.S. GAAP. Under this method of accounting,

GigCapital5, Inc. will be treated as the acquired company for financial reporting purposes. This determination was primarily based on QT Imaging, Inc. s operations comprising substantially all of the ongoing operations of the

post-combination company, QT Imaging, Inc. s senior management comprising substantially all of the senior management of the post-combination company and the existence of a majority voting interest in the post-combination company. Accordingly,

for accounting purposes, the business combination is treated as the equivalent of QT Imaging, Inc. issuing stock for the net assets of GigCapital5, Inc., accompanied by a recapitalization. The net assets of GigCapital5, Inc. is stated at historical

cost, with no goodwill or other intangible assets recorded. Operations prior to the business combination are the historical operations of QT Imaging, Inc.

Basis of Pro Forma Presentation

historical financial information has been adjusted to give pro forma effect to events that are related and/or directly attributable to the business combination, are factually supportable and, with respect to the pro forma statements of operations,

are expected to have a continuing impact on the results of the post-combination company. The unaudited pro forma condensed combined financial information is for illustrative purposes only. The financial results may have been different had the

companies always been combined. You should not rely on the unaudited pro forma condensed combined financial information as being indicative of the historical results that would have been achieved had the companies always been combined or the future

results that the post-combination company will experience. QT Imaging, Inc. and GigCapital5, Inc. have not had any historical relationship prior to the business combination. Accordingly, no pro forma adjustments were required to eliminate activities

between the companies.

PRO FORMA CONDENSED COMBINED BALANCE SHEET AS OF SEPTEMBER 30, 2023

PRO FORMA CONDENSED COMBINED BALANCE SHEET AS OF SEPTEMBER 30, 2023 (CONTINUED)

PRO FORMA CONDENSED COMBINED BALANCE SHEET AS OF SEPTEMBER 30, 2023 (CONTINUED)

Pro Forma Adjustments to the Unaudited Condensed Combined Balance Sheet

(A) To reflect the December 2023 redemption of 2,385 shares of GigCapital5 common stock as if it had occurred as of September 30, 2023.

(A1) To reflect the March 2024 redemption of 848,003 shares of GigCapital5 common stock as if it had occurred as of September 30, 2023.

(A2) Reflects the additional proceeds received prior to the Closing of $435,000 in advances under the GigCapital5 Working Capital Note, an additional $297,247

received under a promissory note with a related party of GigCaptial5 and an additional $55,000 received under QT Imaging s working capital notes to increase the principal amount of this note to $705,000.

(A3) Reflects interest income of $452,928 earned by the trust account prior to the Closing.

(A4) Reflects amounts withdrawn from the trust account to pay taxes.

(A5) To reflect the release of $13,952,527 held in the Trust Account after giving effect to the December 2023 redemptions, including additional extension

payments deposited or expected to be deposited in the Trust Account through the Closing and $138,045 of interest receivable by the Trust Account as all amounts held in the Trust Account are to be released upon the consummation of the Business

Combination to either be used to satisfy the exercise of redemption rights or for use by the Combined Company.

(B1) To reflect cashless exercise of

In-the-Money Company Warrants into 16,320 shares of QT Imaging Common Stock prior to the Closing as if the Closing had occurred on September 30, 2023. Upon consummation of the Business Combination, the shares of QT Imaging Common Stock were

converted into 5,594 shares of Combined Company Common Stock. The terms of the In-the-Money Company Warrants have not been modified.

receipt of $200,000 cash to record a note payable to related party from a Senior Secured Convertible Note of $200,000 issued by QT Imaging from a related party of GigCapital5. Each of the Senior Secured Convertible Notes of issued by QT Imaging has

as one of its terms and conditions that the notes are payable upon maturity at an amount equal to the outstanding note multiplied by 120% (the Repayment Premium ). If cash repayment is not elected by the noteholder, the note shall

automatically convert immediately prior to the Closing of the Business Combination into such number of validly issued, fully paid and non-assessable shares of QT Imaging Common Stock that upon the completion

of the Business Combination and the application of the Exchange Ratio will be exchanged for such consideration as is provided for in the Business Combination Agreement, including that number of shares of Combined Company Common Stock as is equal to

100,000 shares of Combined Company Common Stock (i.e., at an implied conversion rate of $2.00 per share of Combined Company Common Stock). The noteholder elected the cash repayment option.

(B3) To reflect the issuance in Notes Payable of a $200,000 Senior Secured Convertible Note with the same terms as the Senior Secured Convertible Note defined

in Note (B2) by QT Imaging to an affiliate of a noteholder of QT Imaging as an expense in compensation for the noteholder subordinating certain of its rights under its note agreement and in lieu of certain placement agent fees to the affiliate. The

noteholder elected to convert the note payable into 100,000 shares of Combined Company prior to the Closing as reflected in Note (J5).

(B5) To reflect the net proceeds under the SEPA for a total of $10,000,000 issued in the form of a pre-paid

advance from Yorkville and evidenced by a convertible promissory note. As consideration for the pre-paid advance and prior to the Business Combination, Yorkville received consideration that a holder of shares of QT Imaging Common Stock was entitled

to receive pursuant to the Business Combination Agreement, including 1,000,0000 shares of GigCapital5 Common Stock. The capitalized terms in this footnote are as defined in the SEPA.

The $10,000,000 promissory note was issued on March 4, 2024 pursuant to Section 2.01 of the SEPA, dated November 15, 2023, between the Company and the Holder.

The note contained the following derivative features ( Derivatives ) that were recognized at fair value:

The fair value of the above Derivatives was calculated using a Monte Carlo simulation, performed by an independent valuation firm. The simulation used as

significant inputs the volatility of QT Imaging equity that was derived based on a comparable peer group of publicly traded companies and the company s stock price on the valuation date based on the $10 per share inferred from the merger

The key inputs into the valuation model included a volatility of 80%, risk-free rate of 5.4% and a fair value of the common stock at

The total value of the Derivatives reflected the combined value of the monthly payment premium, reduction to that premium by the

payment discount, and the value of the conversion right. The values of the failure to timely convert and corporate event features were deemed to be de minimus.

In accordance with ASC 470-20, the proceeds of $10,000,000 will be recorded between the promissory note and Common Stock less debt origination costs of

$975,000, consisting of a $375,000 commitment fee for the SEPA and original issue discount of 6% for the Pre-Paid Advance, on a relative fair value basis. A structuring fee of $20,000 will be expensed.

(B6) To reflect the issuance of the number of shares of QT Imaging Common Stock, as consideration for the

September and December 2023 Non-Redemption Agreements ( NRA ) Stockholders agreeing not to redeem or to reverse any redemption demands previously submitted in connection with the respective

extensions, that will convert into an aggregate of 427,474 of the Combined Company at a fair value of $3.53 per share after the Closing. The shares will be fully vested, nonforfeitable equity instruments upon issuance to the December 2023 NRA

Stockholders and in connection with the September and December 2023 NRA that included no further obligation (of the September and December 2023 NRA Stockholders) after entering into the NRA. QT Imaging will recognize the issuance of the QT Imaging

Common Stock as general & administrative expense in accordance with ASC 718-10.

proceeds of $1,100,000 from four investors comprised of $600,000 under Senior Secured Convertible Notes issued by QT Imaging and $500,000 under the Stock Subscription Agreements. The $600,000 Senior Secured Convertible Notes and the Stock

Subscription Agreements of $500,000 will convert into an aggregate of 200,000 shares of the Combined Company after the Closing (i.e., at an implied conversion rate of $2.50 per share of Combined Company Common Stock). In connection with the

transaction, investors that subscribed to the purchase of at least $1,000,000 of QT Imaging Common Stock (the Subscription Shares ), were each awarded an additional number of shares of QT Imaging Common Stock ( Early Investor

Consideration Shares ) that upon the completion of the Business Combination and the application of the Exchange Ratio will be exchanged into an aggregate of 150,000 shares of the Combined Company.

Each of the Senior Secured Convertible Notes issued by QT Imaging has as one of its terms and conditions that the notes are payable upon maturity at an amount

equal to the outstanding note multiplied by 120% (the Repayment Premium ). If cash repayment is not elected by the noteholder, the note shall automatically convert immediately prior to the Closing of the Business Combination into such

number of validly issued, fully paid and non-assessable shares of QT Imaging Common Stock that upon the completion of the Business Combination and the application of the Exchange Ratio will be exchanged for such consideration as is provided for in

the Business Combination Agreement, including that number of shares of Combined Company Common Stock as is equal to 100,000 shares of Combined Company Common Stock (i.e., at an implied conversion rate of $2.00 per share of Combined Company Common

In accordance with ASC 470-20, the proceeds of $1,100,000 will be recorded between the Senior Secured

Convertible Notes and the Stock Subscription Agreements on a relative fair value basis. Fair value of the Stock Subscription Agreement was calculated based on assumed issuance of the Subscription and Early Investor Consideration Shares. The

Repayment Premium represents a redemption feature, which is required to be bifurcated from the debt host and recorded as a derivative liability. As of the date of issuance of the Senior Secured Convertible Notes, management had estimated that the

probability of an event of default was negligible; accordingly, the fair value of the derivative liability was de minimis at the date of issuance. The Senior Secured Convertible Notes were recorded net of a $281,275 deemed debt discount as a result

of the relative fair value allocation of proceeds. In accordance with ASC 835-30, the deemed debt discount is amortized initially as interest expense over the life of the loan then fully expensed upon conversion.

(B8) To reflect the payment of the required non-redemption payments as defined in the November 2023 Non-Redemption Agreements for an aggregate of 1,200,000 shares not redeemed times the redemption price less $2.50 per share plus 50,000 structuring shares at the redemption price. QT Imaging will recognize the

payment as general & administrative expense in accordance with ASC 718-10.

(B9) To reflect the issuance

of Cable Car Promissory Note in the amount of $1,500,000 and the issuance of 180,000 shares of Combined Company in lieu of any simple or in-kind interest on the Closing. In accordance with ASC 470-20, the proceeds of $1,500,000 will be recorded between the promissory note and Common Stock on a relative fair value basis.

(C) To reflect the redemption of 848,003 shares by Public Stockholders of GigCapital5 at the Closing, 1,250,000 shares not redeemed and payments made

under the November 2023 Non-Redemption Agreements. To reflect the transfer of the remaining 1,264,590 shares of the Common Stock to permanent equity ($13,970,677). See Note (B8) for payments made under the November 2023 Non-Redemption

(D1) To reflect the payment of the Working Capital Notes ($556,350) at the Closing.

(D2) To reflect the payment of the non-convertible Working Capital Notes ($297,247) at the Closing.

(E) To reflect the payment of certain expenses at the Closing as if the Closing, as if the Closing had occurred on September 30, 2023.

(F) To reflect the payment of amounts due at the Closing to related parties and insiders of GigCapital5, as if the Closing had occurred on September 30,

(G) To reflect the reclass to negative additional paid-in capital.

(H) Eliminates the historical par value of QT Imaging. The par value of the Combined Company Common Stock will be $0.0001 per share.

(I1) Reflects the recording of the estimated GigCapital5 Transaction Expenses not reflected in the historical statements. The accrual of $1,054,533 reflects

total GigCapital5 Transaction Expenses of $8,683,667 less amounts already paid of $350,000 and amounts recorded in accounts payable of $419,134, accrued legal fees of $3,500,000, accrued advisory fees of $600,000 and deferred underwriting fees

(I2) Reflects the recording of the estimated Company Transaction Expenses not reflected in the historical statements. The accrual of