Company: CNCKW
Filing Date: 2025-08-28
Form Type: 6-K
Source: 0001213900-25-081742
Chunk: 1

Company: Coincheck Group N.V.
Filing Date: 2025-08-28
Form: 6-K
Chunk 1
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), to the extent not superseded by documents or reports subsequently filed or furnished. EXHIBIT INDEX

1

SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

| Date: August 28, 2025 |     | COINCHECK GROUP N.V. 
 By:                  |     | /s/ Gary A. Simanson                  |
|:----------------------|:----|:---------------------|:----|:--------------------------------------|
|                       |     | Name:                |     | Gary A. Simanson                      |
|                       |     | Title:               |     | Chief Executive Officer and President |

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