DeWolf Realty Co., Inc., founded in 1879, is the oldest active real estate company in the United States. The firm was founded by William Morrison DeWolf, who started his career in real estate working for Charles Capp, for whom Capp Street was named.

In 1916, William Morrison DeWolf passed away and the ownership of the firm went to his son, William Waldo DeWolf. During the Depression, Bill DeWolf applied for and received one of two HOLC Sales Brokers contracts awarded by the government for the sale of government properties. During World War II, DeWolf was also awarded a contract for the management of government housing in San Francisco and was an authorized Veteran's Administration property manager for over forty years.

On July 1, 1950, Bill DeWolf decided he wanted to retire and asked O.A. "Bill" Talmage to take over active management of the firm. Mr. Talmage active in developing land and building homes in the suburbs of San Francisco, specifically in Novato, Petaluma, Atwater, Sacramento, and Los Gatos. The firm was also very active in the developing of apartment buildings in San Francisco.

1962, after the passage of the "Cigar Tax Act" which provided for the establishment of Real Estate Investment Trusts (REITs), Mr. Talmage along with three other prominent San Franciscans started Western Investment Real Estate Trust, the second oldest REIT in the United States, and until it was sold, the largest REIT on the West Coast. For the first 20 years of its operation, Western Investment was managed out of the DeWolf Realty Co., Inc. office.

In June of 1982, O.A. Talmage retired from DeWolf Realty Co., Inc. and Mr. Talmage's son William A. Talmage took over management of the firm. Today, DeWolf Realty Co., Inc.'s focus is the management of residential and commercial property throughout Northern California, with its main office still located on California Street near 6th Ave., where it has been for over a century.