Regulators asked the country’s largest banks to model losses from a major crypto exchange breach, while Brazil’s biggest platform froze withdrawals after a $38-49 million theft.
MoneyTurkey Crypto Desk | 3 November 2026
Key points
- South Korea’s financial regulator asked its biggest banks to quantify how a major crypto hack would affect their balance sheets.
- Mercado Bitcoin reported a $38 million loss, froze deposits and withdrawals, and pledged to cover customer funds after the breach.
South Korea’s financial regulator has asked the country’s largest banks to estimate how a major crypto exchange hack would hit their books. The request follows a weekend breach at Brazil’s biggest crypto platform, Mercado Bitcoin, which lost between $38 million and $49 million and suspended all deposits and withdrawals. The move signals that regulators now treat crypto-related losses as a potential banking-sector risk.
What happened
CoinDesk reported that South Korea’s financial regulator sent a formal questionnaire to its largest banks asking them to model the impact of a major crypto exchange hack on their capital and liquidity.
The request comes days after Mercado Bitcoin disclosed a security breach on November 2 that drained assets across at least ten blockchains.
Decrypt reported that the exchange valued the stolen assets at $38 million and said it had already blocked $11 million with help from Tether, Circle, Paxos, BRL1 and Chainalysis.
Blockchain analytics firms gave higher estimates: Arkham traced at least $46 million and Chainalysis put the figure at about $49 million, with nearly $10 million frozen.
Tether separately froze more than $4.5 million in USDT linked to the incident.
Mercado Bitcoin said no customer funds were lost and no personal data leaked, but deposits and withdrawals remain suspended with no restart date announced.
Brazil exchange response
Mercado Bitcoin stated that customer balances remain recorded in their accounts and that the exchange will absorb the loss.
The platform has not disclosed how the attackers gained access or whether the $38 million figure includes frozen funds.
The exchange said it would post updates on X and resume service once full security is restored.
Separate GitBook incident
Decrypt also reported that documentation platform GitBook suffered an AI-assisted breach on November 2 that exposed infrastructure credentials.
GitBook took its authenticated services offline, revoked tokens, and later restored access, though some services remain degraded.
The company said the attack used AI agents to obtain integration tokens, Git Sync secrets and API tokens, but did not link the incident to Mercado Bitcoin.
Why it matters
The South Korean regulator’s request shows that authorities now view crypto-exchange failures as a direct risk to traditional banks.
Mercado Bitcoin’s pledge to cover losses cannot be verified externally, as exchanges are not required to publish detailed financial statements.
The episode follows Binance’s October 29 breach, which the FBI attributed to North Korea’s TraderTraitor group, though Mercado Bitcoin has not linked its incident to that attack.
What to watch
- South Korea regulator’s next steps on bank crypto exposure
- Mercado Bitcoin withdrawal restart date
- Tether’s handling of the frozen $4.5 million in USDT
- GitBook service restoration timeline
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For information only. Not investment advice.
Sources
- CoinDesk: https://www.coindesk.com/business/2026/11/03/south-korea-asks-its-biggest-banks-how-a-major-crypto-hack-would-hit-them
- Decrypt: https://decrypt.co/382459/brazil-mercado-bitcoin-will-refund-users-40-million-hack
- Decrypt: https://decrypt.co/382465/crypto-docs-gitbook-ai-agent-security-breach
