Did overweighting big tech stocks drive fund manager outperformance?
Core argument: Active managers' excess returns versus the S&P 500 since January 2023 cluster around those with an average aggregate overweight to the Magnificent 7 stocks.
The first chart shows each manager’s average aggregate Mag 7 stock overweight or underweight since January 2023 on the X axis, and the manager’s excess return vs the S&P 500 on the Y axis. The outperformers are highly clustered around managers that were overweight Mag 7 stocks. We then computed the share of total months that each manager was overweight Mag 7 stocks on an individual basis; results were similar with outperformers clustered around managers that were consistently overweight each one of the Mag 7 stocks.

