Ken Griffin's firm gained about 14% in its stock-focused hedge fund in July, as Citadel's purchase of the bulk of the stock portfolio from the AI-focused hedge fund Situational Awareness helped propel performance last month. Citadel snapped up the AI stocks from Situational on July 30, at a discount of greater than 10%, as the San Francisco-based firm was scrambling to raise cash to meet margin calls following a brutal tech selloff. Many of the market's AI darlings, from Sandisk to Microsoft, then rallied.

For Wellington, July was the best month since April 2022, when Citadel's commodities traders were well-positioned for the volatility that followed Russia's full-scale invasion of Ukraine. July was a bruising month for the broader hedge-fund industry, with popular strategies such as betting on momentum, chip makers or other AI winners coming under pressure. Global stock-picking funds lost 4.3% in July, their second-worst month in the past four years, according to Goldman Sachs's prime-brokerage division.

Volatility led many fund managers to cut risk and exit positions.