Jane Street, a leading quantitative trading firm, significantly reduced its Bitcoin ETF holdings by 71% in Q1 2026, while increasing its investments in Ethereum-based ETFs by $82 million. The firm's 13F filings reveal a reduction in its stake in BlackRock's iShares Bitcoin Trust to 5.9 million shares, valued at approximately $225 million, and a 60% cut in its position in the Fidelity Wise Origin Bitcoin Fund. Conversely, Jane Street nearly doubled its holdings in BlackRock's iShares Ethereum Trust and increased its allocation to Fidelity's Ethereum fund. The firm also adjusted its positions in other crypto-related assets, reducing its stake in MicroStrategy by 78% and increasing its holdings in Galaxy Digital, Riot Platforms, and Coinbase. These moves are part of Jane Street's sophisticated derivatives strategies, which include delta-neutral trades that may not be fully visible in 13F filings. The firm's trading revenue reached a record $16.1 billion in Q1 2026, highlighting its significant market influence.