Insurance company HealthSpring represents founder Herb Fritch’s third health care organization.

The company grows rapidly. In 2010, HealthSpring is the only Tennessee company listed in Fortune magazine’s 100 fastest-growing companies.

Fritch serves as chairman of the board and CEO until the company’s $3.8-billion acquisition by Cigna in 2011. That deal forms Cigna-HealthSpring, where Fritch will stay on as CEO.