On January 1, 1886, L.M. Studevant, a local bookkeeper, founded The Peoples Insurance Agency for Fire Insurance and on October 23 of that year, was the main organizer of the Peoples Building and Loan Association of which he became secretary.

In January of 1899, William Kingseed, Peoples Treasurer, was added to the agency and it was then called Studevant & Kingseed Insurance Agency, "The best and largest in Shelby County, Fire, Tornado, Life, and Accident Insurance" at the Peoples Savings and Loan Association.

H.T. Ruese became manager of the agency in 1908. He, together with J.L. Dickensheets, purchased the agency in July 1920. When Dickensheets died in 1926, the Agency's name was changed to Ruese Insurance Agency and Lloyd Ruese joined his father on August 3, 1926, in the Thedieck Building.

Robert Dunham, Lloyd's son-in-law, joined the Ruese Agency in 1953, becoming part owner in 1964. Paul Gahagan of Westfield Insurance Company joined the agency in 1969, becoming part owner in 1972 upon Lloyd's retirement. The agency then moved to 116 South Main, on the square.

The agency merged with Joseph Belser's Agency on January 1, 1975, and became Ruese Insurance Agency, Inc. Joe retired in April of 1979, and Mark Dunham, son of Robert, joined the agency in 1980.

Robert Dunham retired March 31, 1987, and Paul Gahagan became sole owner.
On July 1st, 1996, Ruese Insurance Purchased the Geimer Insurance Agency of Sidney.

Paul Gahagan retired in October of 1996 and Mark Dunham and Ralph Keister III purchased the agency.

In January of 2001, the Ruese Insurance Agency merged with the Ratermann Insurance Agency in Fort Loramie. With the merger, Steve Ratermann became an owner in the Agency. This merger represented Ruese's first office outside of Sidney.
On June 1st, 2001, Ruese Insurance Agency purchased the Bennett Insurance Agency of Sidney. This represented the consolidation of the two oldest insurance agencies in Sidney. The acquisition of the Bennett Agency brought the total number of employees to 13.

Ruese Insurance expanded into Miami County in February of 2003 when it purchased the McColloch-Baker Insurance Service in Piqua.