Bithumb fined US$136,000 over data transfers

• South Korea's privacy regulator has fined Bithumb US$136,000 for transferring user information to overseas cryptocurrency exchanges without obtaining separate consent.
• The regulator said the exchange breached personal information protection rules while sharing order book data and processing virtual asset transfers.
• The decision comes as South Korea increases regulatory oversight of cryptocurrency exchanges ahead of new tax rules due to begin in 2027.

South Korean cryptocurrency exchange Bithumb has been fined US$136,000 after the country's Personal Information Protection Commission found it transferred customer information to overseas cryptocurrency exchanges without obtaining the required user consent.

The regulator said the violations occurred between September and November 2025 when Bithumb shared Tether (CRYPTO:USDT) order book information with BingX despite only receiving consent for data sharing with Stellar, while also transferring user information to 13 overseas exchanges.

"The Personal Information Protection Commission determined that there is a necessity to provide personal information for anti-money laundering purposes when transferring virtual assets to other exchanges, but regarding the overseas transfer of personal information and the data subject's right to self-determination, it is necessary to strictly comply with the requirements and procedures stipulated in the Protection Act," the commission said.

The commission said anti-money laundering requirements do not remove the obligation for exchanges to obtain separate consent before transferring personal information overseas under South Korea's privacy laws.

The fine follows increased regulatory scrutiny of Bithumb, including a six-month business suspension imposed in March that was later overturned by a court, as well as a police investigation into alleged nepotism involving South Korean lawmaker Kim Byung-gi.

South Korea's Finance Ministry has also confirmed that a 22% tax on cryptocurrency gains will take effect from January 2027 after several implementation delays.

The latest enforcement action comes as South Korean authorities continue strengthening oversight of the digital asset sector, with approximately 16 million South Koreans reported to own cryptocurrency as of March 2025.