Taiwanese cryptocurrency exchange BitoPro is suspected to have lost over $11.5 million worth of tokens in a May 8 exploit, widely-followed blockchain sleuth ZachXBT said in his Telegram group on Monday.

The exploit involved unauthorized access to BitoPro’s hot wallets across multiple blockchains, including Ethereum, Tron, Solana, and Polygon.

The stolen assets were then sold on decentralized exchanges, with proceeds laundered through privacy protocols such as Tornado Cash and Thorchain, and eventually moved to Wasabi Wallet, a Bitcoin mixing service.

BitoPro has not issued any public statements acknowledging the breach since the supposed explicit. Users were informed of a temporary service suspension due to «system maintenance” last month, and there was little social chatter in popular crypto X circles around the incident at the time.

“BitoPro has yet to formally disclose the incident on X or Telegram and told users the exchange was just offline for «maintenance,” ZachXBT said.

BitoPro has been based in Taiwan since 2018 and is operated by BitoGroup. It is mostly focused on the local market and mainly supports Taiwanese dollar (TWD) fiat pairs for major tokens such as bitcoin BTC, ether ETH and others.

It processed over $20 million in trading volumes in the past 24 hours, data shows, and is the top locally-focused exchange by that metric.

Malicious Ethereum contracts designed to drain wallets with weak security aren’t profiting from the operation, crypto market maker Wintermute said Friday, identifying these contracts as «CrimeEnjoyors.»

The whole issue is tied to the Ethereum Improvement Proposal (EIP)-7702, part of the Pectra upgrade that went live early last month. It allows regular Ethereum addresses, secured by private keys, to temporarily operate as smart contracts, facilitating batched transactions, password authentication and spending limits.

The regular Ethereum addresses delegate control of their wallets to smart contracts, granting them permission to manage or move their funds. While it has simplified the user experience, it has also created a risk of malicious contracts draining funds.

As of Friday, more than 80% of delegations made through EIP-7702 involved reused, copy-and-paste contracts designed to automatically scan and identify weak wallets for potential theft.

«Our Research team found that over 97% of all EIP-7702 delegations were authorized to multiple contracts using the same exact code. These are sweepers, used to automatically drain incoming ETH from compromised addresses,» Wintermute said on X.

«The CrimeEnjoyor contract is short, simple, and widely reused. This copy-pasted bytecode now represents the majority of all EIP-7702 delegations. It’s funny, dark, and fascinating all at once,» the market maker added.

Notable cases include a wallet that lost nearly $150,000 through malicious batched transactions in a fishing attack, as anti-scam tracker Scam Sniffer noted.

Still, the large-scale money drain has not been profitable for the attackers. The CrimeEnjoyors spent approximately 2.88 ETH to authorize around 79,000 addresses. One particular address –0x89383882fc2d0cd4d7952a3267a3b6dae967e704 – handled more than half of these authorizations, with 52,000 permissions granted to it.

Per Wintermute’s researcher, the stolen ether can be traced by analyzing the code of these contracts. For the above example, the ETH is destined to flow the address –0x6f6Bd3907428ae93BC58Aca9Ec25AE3a80110428.

However, as of Friday, it had no inbound ETH transfers. The researcher added that this pattern appears consistent across other CrimeEnjoyors as well.

Japan’s Metaplanet said on Monday it has purchased additional 1,088 bitcoin BTC to bring its total holdings to over 8,888 BTC, now worth over $930 million.

The latest acquisition cost the company 16.885 billion Japanese yen ($117.5 million), with an average purchase price of approximately 15.5 million yen ($108,051) per bitcoin, per a disclosure.

Metaplanet’s aggressive bitcoin accumulation strategy, which began with its official adoption of a Bitcoin treasury policy in April 2024, has propelled the firm to the top spot among corporate BTC holders in Asia and the top ten globally.

The firm has now added 7,126 BTC 2025 so far, pacing to its year-end target of 10,000 BTC. Its latest move follows the company’s issuance of $50 million in zero-interest bonds last week, providing additional capital for BTC purchases without diluting existing equity.

Metaplanet reported a BTC Yield of 66.3% for year-to-date, BTC Gain, expressed in Bitcoin terms, rose to 2,684 BTC, while BTC ten Gain translated to approximately 40.5 billion yen.

BTC was hovering over $105,000 in Asian hours Monday, little changed over the past 24 hours.