JPMorgan Chase scaled back the financing it extended to Jane Street as the trading firm's push into the bond market put it in direct competition with the Wall Street bank. The biggest US bank significantly curbed the lending it provided to Jane Street for its bond trading last year, according to people familiar with the decision. The reduction reflected roughly 5 per cent of Jane Street's total fixed-income financing across banks and had no material impact on its revenues in 2025, one of the people added.

JPMorgan's move underscores how Jane Street's rapid transformation into a major force in markets has placed the secretive group in competition with banks that had long dominated trading. The decision came after Jane Street began making markets in US Treasuries, directly encroaching on a major line of business for banks. Jane Street traded more than $900bn in bonds last year.

Proprietary trading firms largely use their own capital but amplify returns through borrowed money. Jane Street generated $40bn in trading revenues last year, just $1bn below JPMorgan's total. The firm booked a $15bn loss in July from wagers tied to AI stocks and an investment in Leopold Aschenbrenner's hedge fund, Situational Awareness. Jamie Dimon has described Citadel Securities as an emerging competitor in his annual letter released in April.