The Insurance Company of North America (INA), the oldest joint stock insurance company in the United States, was formed in 1792 in Philadelphia, Pennsylvania. The business grew out of the idea of the tontine, in which investors contribute equally to a joint fund and the money is given to the last individual living. Although similar schemes had recently failed in Boston and New York, the INA proved successful in its initial marine insurance ventures. They offered to secure any bottom sailing from between Philadelphia, Pennsylvania and Charleston, South Carolina or from New York for up to $20,000 at a 1% premium. This system was a distinct improvement over the previous method of insuring cargo, in which a merchant contracted with a private (and unregulated) underwriter and lost any money he had invested should the underwriter fold. The INA became the new nation's largest marine insurer within its first decade. It began offering fire insurance in 1794 and even dabbled in life insurance during the late 1700s and early 1800s. As America grew, the INA began appointing agents in such distant territories as California and Texas, thus establishing itself as the first insurance company to offer its services on a national level. These agents eventually formed the model for the later local agency system.

In 1898 Benjamin Rush, Thomas Young, and Harry Farnham devised a new, scientific method of classifying marine risks. Their work allowed the company to write vastly improved policies and inaugurated 21 straight years of profitable operation. When Rush became President of the INA in 1916, he expanded the company's scope to allow it to write every form of insurance policy known except for life. After World War I ended, Rush led an expansion program in which INA acquired such smaller insurance agencies as the Philadelphia Fire and Marine Insurance Company, Alliance Casualty Company, and the Indemnity Insurance Company of North America. The company re-entered life insurance in 1956, when it acquired the Life Insurance Company of North America. In 1982 the INA merged with the Connecticut General Insurance Company to form CIGNA. The organization began downsizing in the late 1990s, selling its U. S. individual life insurance and annuity operations to the Lincoln National Corporation (1998) and its domestic and international property and casualty operations to ACE Limited of Bermuda (1999). Thus, although the company's successor continues to operate, it no longer enjoys the diversity that its predecessor established.