National Currency Bank of New York and started the First National Bank of Detroit, and the Columbia Bank in Chatham, New York. On September 3, 1885, he was one of three incorporators of The Graphic Mining & Smelting Company in Chicago Illinois with $300,000 capital stock. That same year, the was a founding trustee of the American Electric Railway Company of New York. The company had $1 million in capital to build locomotive engines and cars. In January 1888, Thompson was one of four investors who bailed out the failing Montgomery & Florida Railway (aka the Alabama & Florida Railroad). In August 1888, when the New York Elevated Railroad merged with the Manhattan Railway Company, Thompson was elected president of the new corporation. In May 1894, Thompson was also elected to the board of the Maritime Canal Company of Nicaragua which was involved with the Nicaragua Canal project. The company had sold more than $22 million in stock in 1894. He became chairman of the company in 1898. Despite being incorporated by Congress, the Maritime Canal Company received no federal funding and ultimately defaulted on the project in 1899 because of lacking funds and the instability of Nicaragua. Philanthropy Thompson and his wife donated large sums of money to numerous organizations, including the American Geographical Society, the Metropolitan Museum of Art, the Union League, and the Williams College Alumni Association. He was key to the construction of the Ontario Orphan Asylum and buildings for the Teachers College, Columbia University. At Williams College, he donated a clock tower to Lasell Gymnasium in 1886. He donated the forty-acre Tallmade Farm to Williams College in 1887. In June 1888, he gave a challenge gift of $25,000 to construct a $100,000 memorial to Dr. Mark Hopkins, provided alumni donated the balance needed. The resulting Mark Hopkins Memorial building contained a library, art gallery, offices, and a room for lectures and recitations. In 1891, he offered to build a new library at his own expense. In 1895, he donated $175,000 for the construction of the Thompson Laboratories. In 1895, he donated $5,000 toward the construction of a new infirmary. He also supported scholarships, the Thompson Fund for lectures, and the annual Thompson Entertainments. At the time of his death, he was the most generous donor in the history of Williams College. in 1898, the New York Times noted that "Mr. Thompson is a veritable fairy