Company: GIGGU
Filing Date: 2025-09-29
Form Type: 425
Source: 0001193125-25-221783
Chunk: 241

Company: GigCapital7 Corp.
Filing Date: 2025-09-29
Form: 425
Chunk 241
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unto duly authorized) as of the date first written above.

| GIGCAPITAL7:                   |     |                     |
| GIGCAPITAL7 CORP.              |     |                     |
| By:                            |     | /s/ Dr. Avi S. Katz |
| Name: Dr. Avi S. Katz          |     |                     |
| Title: Chief Executive Officer |     |                     |
| SPONSOR:                       |     |                     |
| GIGACQUISITIONS7 CORP.         |     |                     |
| By:                            |     | /s/ Dr. Avi S. Katz |
| Name: Dr. Avi S. Katz          |     |                     |
| Title: Chief Executive Officer |     |                     |

[Signature Page to Sponsor Support Agreement]

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed (where applicable, by their respective officers or other authorized Persons thereunto duly authorized) as of the date first written above.

| THE COMPANY:                   |     |                   |
| HADRON ENERGY, INC.            |     |                   |
| By:                            |     | /s/ Samuel Gibson |
| Name: Samuel Gibson            |     |                   |
| Title: Chief Executive Officer |     |                   |

[Signature Page to Sponsor Support Agreement]

Exhibit 10.2

Execution Version

Transaction Support Agreement

TRANSACTION SUPPORT AGREEMENT, dated as of September 27, 2025 (this “”), by and among GigCapital7 Corp., a
Cayman Islands exempted company (which shall transfer by way of continuation and domesticate as a Delaware corporation prior to Closing) (“”), and certain of the stockholders of Hadron Energy, Inc., a Delaware
corporation (the “”), whose names appear on the signature pages of this Agreement (each, a “” and, collectively, the “”).

RECITALS

WHEREAS,
GigCapital7, MMR Merger Sub, Inc., a Delaware corporation and wholly owned subsidiary of GigCapital7 (“”), and the Company have negotiated a Business Combination Agreement in the form attached hereto as
(the “”; terms used but not defined in this Agreement shall have the meanings ascribed to them in the BCA), which provides, among other things, that, upon the terms and subject to the conditions thereof, Merger Sub will merge
with and into the Company (the “”), with the Company surviving the Merger as a