Index-rebalancing trades deliver billions to hedge funds

Hedge funds captured large profits from index-rebalancing trades in the second quarter after about $1.3 trillion of index-related trading and SpaceX’s rapid addition to the Nasdaq 100. Two rebalancing teams at Millennium Management generated roughly $3.7 billion in combined profits during the month.

The strategy involves buying shares expected to be added to major indices and selling those likely to be removed ahead of passive index-tracking funds that must adjust holdings.

Scheduled changes to the S&P Dow Jones and Russell indices, together with SpaceX’s inclusion following its IPO, created a concentrated window of predictable buying and selling in Q2. Analysts estimate SpaceX’s addition prompted about $4.3 billion of passive buying.

Large multi-strategy hedge funds with big balance sheets and access to financing were able to build sizeable positions before passive funds executed required trades. Other firms, including Citadel and ExodusPoint, reduced exposure earlier in 2025 after losses during a period of higher volatility.

Market participants note that correctly forecasting index additions and deletions, having capital to take substantial positions, executing orders quickly and estimating passive fund volumes are key to performance. Recent rule changes by index providers have shortened the inclusion timetable for newly listed mega-cap companies, increasing how often large rebalancing events occur.

Many newly listed firms have limited free float initially, so the passive buying tied to index inclusion can be smaller than a company’s full market value. That can reduce the size of forced purchases and limit potential profits from positioning ahead of rebalances.

Market participants are watching expected initial public offerings from several artificial-intelligence related companies for comparable rebalancing activity. The second-quarter results reflected a period in which calendar-driven index rules produced large, short-term trading flows that some well-funded managers were positioned to exploit.