Company: QTIWW
Filing Date: 2025-12-31
Form Type: 424B3
Source: 0001628280-25-059235
Chunk: 443

Company: QT IMAGING HOLDINGS, INC.
Filing Date: 2025-12-31
Form: 424B3
Chunk 443
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<div align='center'>F-79</div>

#### QT IMAGING HOLDINGS, INC.

### Notes to Condensed Consolidated Financial Statements
<div align='center'>(Unaudited)</div>

to items reported separately and recognizes the effect of changes in enacted tax laws or rates in the interim periods in which the changes occur.

The Company’s effective tax rate is 0% for the three and nine months ended September 30, 2025 and 2024. The Company expects that its effective tax rate for the full year 2025 will be 0%.

On July 4, 2025, the U.S. enacted H.R.1, “A bill to provide for reconciliation pursuant to Title II of H. Con. Res. 14,” commonly referred to as the One Big Beautiful Bill Act (the “OBBBA”). The legislation, among other things, makes a favorable change to the business interest expense limitation and makes permanent 100% bonus depreciation for qualifying assets and immediate expensing for domestic research and experimentation expenses. The Company does not expect the OBBBA to have a material impact on its consolidated financial statements, including the income tax effects.

#### 14.

#### Related Party Transactions

#### Convertible Notes Payable
In July 2020, the Company issued three convertible notes to three of its stockholders for advances up to $3,500,000 in principal (the “2020 Notes”) and bearing annual interest of 5% on any amounts drawn. An additional note was issued in March 2022 as part of the 2020 Notes, but with an annual interest rate of 8%. All principal and interest payments were initially due on or before July 1, 2025. In connection with the issuance of the Lynrock Lake Term Loan, on February 26, 2025, the maturity date on these convertible notes payable was extended to October 21, 2027.

The 2020 Notes are convertible, at the holder’s option, into shares of common stock of the Company at the lower of $43.77 per share or the offering price in a financing of at least $5,000,000 in equity from unaffiliated parties. As of September 30, 2025, an aggregate o f 88,402 s hares of common stock would be issued if the entire principal and interest under the 2020 Notes was converted. Management assessed whether the embedded features in the 2020