BlackRock, the world’s biggest asset manager, is doubling down on crypto. On Tuesday, September 16, 2025, the company purchased more than $620 million worth of Bitcoin (BTC) and Ethereum (ETH) in a single day.

Data shows that BlackRock added 2,270 BTC, worth about $262.7 million, and 78,922 ETH, worth $357.4 million. This brings its total Bitcoin stash to more than 757,000 BTC, valued at $87.23 billion, and Ethereum holdings to 3.68 million ETH, valued at $16.95 billion.

According to analyst Thomas Fahrer, BlackRock now controls 762,000 BTC through its iShares Bitcoin Trust (IBIT). A chart of IBIT flows shows how quickly BlackRock has been stacking Bitcoin since the fund launched. 

From early 2024 through mid-September 2025, IBIT’s Bitcoin holdings surged from under 100,000 BTC to more than 751,000 BTC, making it one of the largest accumulators in history.

Total BlackRock crypto portfolio

According to Arkham data, the company’s total crypto portfolio jumped from $99.88 billion on September 9 to $104.18 billion on September 16, a one-week increase of $4.31 billion. Most of that came from gains in Bitcoin and Ethereum. BTC rose by nearly $4,000 (+3.59%) in the week, adding $3.66 billion in value to BlackRock’s position, while ETH climbed about $292 (+6.78%), adding $645 million.

One surprising detail is that while Ethereum’s dollar value grew, the number of ETH in BlackRock’s wallets actually fell by nearly 100,000 tokens during the same period. This drop in token count, combined with the higher price, highlights how volatile institutional trading activity can appear on-chain.

Overall, BlackRock’s move adds to the growing narrative of Wall Street giants cementing their dominance in digital assets. With Bitcoin and Ethereum still the top two cryptocurrencies by market value, the company’s aggressive buying shows that large financial players continue to see long-term potential.