Affiliated Managers Group, a publicly traded asset management company that backs investment firms including AQR Capital Management, has become the target of a short-selling campaign by Orso Partners.

The short seller has disclosed a position betting against AMG's stock price, with the investment thesis reportedly focused on the company's tax-loss harvesting strategies. Tax-loss harvesting is a common investment practice where securities are sold at a loss to offset capital gains for tax purposes.

Following the disclosure of Orso Partners' short position, AMG shares declined in trading. The company manages a portfolio of boutique investment management firms and generates revenue primarily through performance fees and management fees from its affiliate partners.

AMG's business model involves taking stakes in independent asset management companies while allowing them to maintain their investment autonomy and entrepreneurial culture. The firm has partnerships with various investment managers across different strategies including quantitative, fundamental equity, fixed income, and alternative investments.

Short-selling campaigns against financial services companies have become increasingly common, with activist short sellers often targeting business practices, accounting methods, or market positioning strategies they view as problematic or unsustainable.