Apparently most of that came from arbitraging bond ETFs and bonds. The spreads started to diverge in early 2020 when covid was just coming out, and Jane Street

Apparently most of that came from arbitraging bond ETFs and bonds. The spreads started to diverge in early 2020 when covid was just coming out, and Jane Street had the balls (and cash) to hold until the spreads converged. Helped significantly by the US fed pumping a bunch of money into the market.