American businesswoman Gayle Cook has an estimated net worth of $4 billion as of March 2013 according to Forbes. She is known to be one of the founders of Cook Group Inc.

After the death of her husband, William Cook, in April 2011, Gayle Cook inherited her husband's shares in Cook Group Inc., a company that manufactures medical devices. It was in 1963 when William Cook and others started the company in an apartment in Bloomington.

Today, Cook Group Inc. operates in numerous offices located in Asia, U.S. and Europe. The company primarily focuses on producing catheters and stents that contain antibiotics. In 2012, the FDA finally released its approval to allow Cook Group Inc. to produce stents that release drugs in the legs through the arteries for the treatment of peripheral artery disease. The company also owns technologies on tissue and cell processing as well as cryopreservation.