Coincheck Began Yen Reimbursements After the NEM Theft

Coincheck announced on March 12, 2018 that it was crediting eligible customers with Japanese yen after NEM was illicitly transferred from the cryptocurrency exchange on January 26. The reimbursement represented a major test of whether a digital-asset venue could absorb a large custody loss without sending affected customers into an insolvency process.

The company set compensation at ¥88.549 for every XEM held in a Coincheck account at 23:59:59 Japan Standard Time on January 26. The cutoff measured customer balances after the unauthorized transfers had occurred but before the exchange had fully resolved the incident.

Coincheck said compensation would appear as yen in customers’ exchange-account balances rather than as restored XEM or direct deposits into bank accounts. Customers who had not completed identity verification were still eligible for the account credit, although verification was required before withdrawing yen. Withdrawal fees continued to apply, and Coincheck warned that bank transfers would be processed in request order.

Compensation was not a return of the stolen tokens

The distinction between reimbursement and asset recovery was material. Customers received a fixed quantity of yen calculated from their January 26 XEM holdings. They did not regain the same number of NEM tokens, and the March 12 notice did not say that Coincheck had recovered the illicitly transferred assets from the attacker.

The fixed conversion also meant individual outcomes depended on each customer’s acquisition cost and on how XEM’s market value changed. Coincheck was consulting Japanese tax authorities about the treatment of the payment, so the event-day record did not establish a universal tax result.

The company separately resumed withdrawals of bitcoin, ether, ether classic, XRP, litecoin and bitcoin cash on March 12. Sales resumed for those assets other than bitcoin, whose sale function had not been suspended. Deposits and purchases were not restored through that announcement, and NEM trading, deposits and withdrawals remained outside the resumed services.

Coincheck therefore was not announcing a complete reopening. It was restoring selected functions after technical checks while keeping other restrictions in place.

The theft had triggered regulatory intervention

Japan’s Financial Services Agency later summarized the January 26 incident as an unauthorized transfer of approximately 523 million XEM belonging to customers, valued at approximately ¥58 billion at the time. Coincheck was then operating as a transitional exchange whose registration application remained under review.

The regulator issued its first business-improvement order on January 29 and began an on-site inspection on February 2. On March 8, the FSA said Coincheck’s management and internal-control systems had serious deficiencies and announced another administrative action through the Kanto Local Finance Bureau.

That sequence made the March 12 compensation institutionally important. Reimbursing customers addressed one immediate consequence of the loss, but it did not resolve the regulator’s findings about governance, security controls or operational oversight. Nor did paying yen prove that the exchange’s revised systems were ready for unrestricted service.

The episode also exposed the difference between blockchain settlement and exchange custody. NEM’s ledger could record the unauthorized transfers, but customers had entrusted Coincheck with the private-key and account infrastructure governing their pooled assets. Their practical recovery depended on the exchange’s balance sheet and reimbursement decision rather than reversal of the blockchain transactions.

What March 12 established

The defensible event-day conclusion is narrow: Coincheck began implementing a yen-based compensation plan and partially restored access to several cryptocurrencies. The fixed rate, eligibility timestamp, account-credit method and withdrawal conditions were publicly specified.

The announcement did not identify the attacker, recover the missing XEM, settle tax treatment, complete Coincheck’s registration or reopen every service. It also did not provide an independently audited aggregate payout figure in the March 12 notice.

Later verification

A Coincheck FAQ updated on October 16, 2018 subsequently stated that the reimbursement was completed on March 12. That later company record confirms completion but does not convert Coincheck’s account credits into recovered XEM or independently verify the company’s total economic cost.