Orso Partners Targets Affiliated Managers Group in Short Position

Orso Partners has initiated a short position against Affiliated Managers Group Inc. (AMG), the investment firm that provides backing for Cliff Asness’s AQR Capital Management. The bet, revealed in a letter to investors, focuses on the risks associated with the rapid expansion of tax-aware long-short strategies. These specialized strategies are designed to reduce tax liabilities for wealthy investors by offsetting gains with losses. This ecosystem has grown significantly as Wall Street seeks new ways to help high-net-worth Americans manage taxable gains following years of strong market performance. Currently, more than $1 trillion is invested in these tax-reduction strategies. AQR Capital Management has been a primary architect of this trend, positioning itself at the forefront of the tax-aware trade ecosystem. As a result, its backer, AMG—which manages approximately $813 billion in assets—has become the target of Orso's bearish outlook. The market impact of this short position may lead to increased volatility for AMG shares as investors evaluate the sustainability and regulatory risks of these tax-optimization products. The move highlights a growing tension between aggressive tax-efficiency strategies and the scrutiny of short-selling firms.