6-K

UNITEDSTATES

SECURITIESAND EXCHANGE COMMISSION

WASHINGTON,DC 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16UNDER

THE SECURITIES EXCHANGE ACTOF 1934

For the month of March 2025

Commission FileNumber: 001-42438

COINCHECK GROUP N.V.

(Translation of registrant’s name into English)

Apollolaan 151

1077 AR Amsterdam

The Netherlands

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F ☒ Form 40-F ☐

Coincheck Group N.V. (“Coincheck Group”) is providing the below update for Coincheck, Inc. (“Coincheck”). This information will also be posted at https://coincheck.com. Coincheck Group (“CNCK” and “CNCKW”), is a public limited liability company and the holding company for Coincheck. Coincheck operates one of the largest multi-cryptocurrency marketplaces and exchanges in Japan and is regulated by the Japan Financial Services Agency. Coincheck provides Marketplace and Exchange platforms on which diverse cryptocurrencies, including Bitcoin and Ethereum, are held and exchanged as well as other retail-focused crypto services.

Coincheck Group uses its website (https://www.coincheckgroup.com/). to distribute company information and makes available free of charge a variety of information for investors, including its filings with the Securities and Exchange Commission (“SEC”), as soon as reasonably practicable after electronically filing that material with, or furnishing it, to the SEC. The information that Coincheck Group posts on its website may be deemed material. Accordingly, investors should monitor Coincheck Group’s website, in addition to following its press releases, filings with the SEC, and public conference calls and webcasts. In addition, investors may opt in to automatically receive email alerts and other information about Coincheck Group when enrolling their email address by visiting the “Email Alerts” section of the Coincheck Group website. Coincheck Group does not incorporate the information contained on, or accessible through, Coincheck Group’s website or related social media channels into this Report on Form 6-K.

Monthly Disclosure

Coincheck, Inc. is reporting the following preliminary monthly disclosure information for the fiscal year ending March 31, 2025. The preliminary numbers in the tables below are based on currently available information. These preliminary estimates have not been audited by any independent registered public accountants, are subject to update and should not be extrapolated for future periods.

Notes

SIGNATURES

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.