A surprise $133 million Bitcoin transfer from Coinbase Institutional stunned the crypto market early on Tuesday, catching attention for its scale and mystery. The 1,234 BTC move — first spotted by Whale Alert — left Coinbase Prime's hot wallet and went to one address flagged unknown, making many wonder who was behind the transaction and why it was made without any public notice.

It did not take long for answers to come to light. 

Blockchain analytics platform Arkham confirmed that the receiving address belongs to Metaplanet Inc., a Tokyo-based public company that is quickly building one of the world's biggest corporate Bitcoin treasuries. The money was sent straight to Metaplanet's cold wallet.

This is the firm's biggest one-day purchase of Bitcoin to date, bringing its total holdings to 12,345 BTC — which are currently worth about $1.33 billion.

Metaplanet has been on a shopping spree throughout 2024, with three major acquisitions this June alone: 1,112 BTC on the 16th; 1,111 BTC on the 23rd and now 1,234 BTC on the 25th — all from the leading U.S. crypto exchange.

The average cost basis for Metaplanet is now at $96,121 per BTC, with the company holding over 12% in unrealized gains. Bitcoin is now worth more than 21% of the company's market cap, which is a big deal.

In fact, it puts the company ahead of Tesla on the list of public Bitcoin holders and makes it the sixth-largest corporate BTC holder worldwide.