Jane Street increased its stake in Fidelity's Wise Origin Bitcoin Fund (FBTC) nearly eightfold during Q3 2026, according to SEC 13F filings. The market maker held 7.01 million FBTC shares worth approximately $509 million as of September 30, up from 886,700 shares at the end of Q2. In contrast, Jane Street trimmed its position in BlackRock's iShares Bitcoin Trust (IBIT) from 24.88 million to 20.22 million shares, valued at roughly $957 million. The firm also expanded its holdings in ARK 21Shares Bitcoin ETF (ARKB) to 11.69 million shares, worth approximately $324 million.