Company: GIGGU
Filing Date: 2025-09-29
Form Type: 425
Source: 0001193125-25-221783
Chunk: 224

Company: GigCapital7 Corp.
Filing Date: 2025-09-29
Form: 425
Chunk 224
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. A copy of the statement provided pursuant to Treasury Regulations Sections 1.897-2(h)(2)and 1.1445-2(c)(3)(i)is attached.

|                  |     | HADRON ENERGY, INC. |     |        |
| Dated: [_], 2026 |     | By:                 |     |        |
|                  |     |                     |     | Name:  |
|                  |     |                     |     | Title: |

2

CERTIFICATE OF NON-U.S. REAL PROPERTY HOLDING
CORPORATION STATUS

PURSUANT TO TREASURY REGULATIONS SECTIONS 1.897-2(h) AND 1.1445-2(c)(3)

Pursuant to the BUSINESS COMBINATION AGREEMENT (“Agreement”) among
GIGCAPITAL7 CORP., a corporation organized under the laws of the State of Delaware (“Acquiror”), HADRON ENERGY, INC., a Delaware corporation (“Target”), and MMR Merger Sub, Inc., a Delaware corporation
(“Merger Sub”), on the Closing Date (as such term is used in the Agreement), Merger Sub shall merge with and into Target, with Target being the surviving company of the merger and Acquiror owning all of the issued and outstanding
shares in the capital of Target.

Section 1445 of the Internal Revenue Code of 1986, as amended (the “Code”),
provides that a transferee of a U.S. real property interest must withhold tax if the transferor is not a U.S. person. In order to confirm that Acquiror, as transferee, is not required to withhold tax upon the receipt of Target stock, the
undersigned, in his capacity as Chief Executive Officer of Target, hereby certifies as follows:

1. As of the date hereof, the stock of
Target to be received by Acquiror pursuant to the Agreement does not constitute a United States real property interest as that term is defined in Section 897(c)(1) of the Code;

2. The determination in Paragraph 1, above, is based on a determination by Target that Target is not and has not been a United States real
property holding corporation as that term is defined in Section 897(c)(2) of the Code during the five-year period ending on the date hereof, as indicated below;

3. Target’s U.S. employer identification number is [_]; and

4. Target’s office