Sio Capital Management

Sio Capital Management is a global equity market neutral healthcare hedge fund headquartered in New York. Founded in 2006 by Dr. Michael Castor, the firm specializes exclusively in healthcare investments across all sub-sectors including biotech, pharmaceuticals, medical devices, insurance, hospitals and services. The team leverages deep expertise in science and industry dynamics to identify mispriced assets and generate risk-adjusted returns for investors[1][2][8].

The firm manages both long and short equity strategies with the goal of capital growth and preservation through prudent stock selection and risk mitigation[1][5]. It invests broadly within healthcare but does not itself conduct drug development or clinical trials.

As of recent filings (Q1/Q4 2024), assets under management range from approximately $335 million (13F securities) to over $1.4 billion total AUM[6][9]. Top holdings include companies such as ICON plc (ICLR), Maximus Inc., Merck & Co., Zimmer Biomet Holdings Inc., Neurocrine Biosciences Inc., among others[6][10].

Key people include founder/portfolio manager Dr. Michael Castor.

The company has no direct pipeline or therapeutic programs as it operates solely as an investor.