John "Jack" Butler held various financial management positions after graduating from Lehigh University with a Bachelor of Science in business administration. He began his business career as a stockbroker in 1958. He joined Chemical Bank in 1960, becoming a bond buyer in the trust department and later was with Franklin National Bank, serving as bond portfolio and underwriting manager until 1968. In 1968 he joined Mark Twain Bancshares in St. Louis as Vice President in charge of investments. He returned to New York in 1970 to assist in the formation of Sterling Grace Municipal Securities Corporation, where he became Executive Vice President in charge of underwriting.

Jack founded Municipal Bond Insurance Association (NYSE: MBI), the world's largest insurance guarantor of municipal and corporate debt securities. He served as President and Chief Executive Officer from 1971 through 1986 and Vice-Chairman from 1986 to 1991. He also founded the MBIA Invitational, a major annual golf and tennis fundraiser for the benefit of Westchester ARC and Special Olympics.

He also founded or was instrumental in the formation of the following business ventures:

Connecticut Bancshares Corporation: founder/director and executive committee member of Northern Connecticut National Bank that merged with Connecticut Bank and Trust Company in 1985.

S&B Insurance Services Company, a financial guarantee insurance brokerage firm: principal founder and first CEO. S&B designed many of the original collateralized insured private debt structures that became the foundation of the structured finance market.

Raised all seed capital for CDC Financial Corporation, now known as Vesta Corporation: Vesta is a highly regarded financier and developer of multi-family rental housing projects.

International Bio-Immune Systems Inc.: principal founder/investor. IBS was first to produce a cancer vaccine that completed all three phases of human clinical trials. The results were published in Cancer, a peer-reviewed journal, demonstrating a 5-year survival rate for lung cancer patients approximately two times greater than the control arm and three times greater than the general population of lung cancer patients.

MediMax, Inc.: primary financier and Chairman until company was sold in 1995. MediMax bought and serviced medical accounts receivables of health care providers.