Company: QTIWW
Filing Date: 2025-12-29
Form Type: S-1/A
Source: 0001628280-25-058960
Chunk: 413

Company: QT IMAGING HOLDINGS, INC.
Filing Date: 2025-12-29
Form: S-1/A
Chunk 413
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The activity for the fair value of the derivative liability during the nine months ended September 30, 2025 was as follows:

<div align='center'>F-66</div>

#### QT IMAGING HOLDINGS, INC.

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

|                                                                  |     | Derivative Liability |         |          |
|:-----------------------------------------------------------------|:----|:---------------------|--------:|---------:|
| Beginning balance, January 1, 2025                               |     | $                    | 303,300 |          |
| Extinguishment upon Termination Agreement                        |     |                      |         | -202,000 |
| Change in fair value                                             |     |                      |         | -101,300 |
| Ending balance, March 31, 2025, June 30, 2025 and September 2025 |     | $                    |       — |          |

The extinguishment of the derivative liability of $ 0and $ 202,000was recorded in other income (expense), net within the condensed consolidated statements of operations and comprehensive loss during the three and nine months ended September 30, 2025, respectively.

#### 4.

#### Inventory
Inventory consisted of the following as of September 30, 2025 and December 31, 2024:

|                 |     |   | September 30, 2025 |     |   | December 31, 2024 |
|:----------------|:----|:--|-------------------:|:----|:--|------------------:|
| Raw materials   |     | $ |          4,488,530 |     | $ |         2,551,947 |
| Work in process |     |   |            731,912 |     |   |           278,869 |
| Finished goods  |     |   |             21,786 |     |   |           309,903 |
| Total           |     | $ |          5,242,228 |     | $ |         3,140,719 |

#### 5.

#### Property and Equipment, Net
Property and equipment, net consisted of the following as of September 30, 2025 and December 31, 2024:

|                                |     |          | Useful Life |   | September 30, 2025 |     |   | December 31, 202