Wakefield-based Franklin Street Properties Corp., an investment firm specializing in real estate, has announced it has priced an underwritten public offering of 8 million shares of its common stock at $13 per share.

The offering was increased from a previously announced offering of 6 million shares. FSP has granted the underwriters a 30-day option to purchase up to an additional 1.2 million shares to cover over-allotments, if any.

The offering is expected to close Sept. 23, subject to customary closing conditions. Robert W. Baird & Co. Inc. acted as sole book-running manager for the offering.

The net proceeds from this offering, after deducting underwriting discounts and commissions, and estimated offering expenses, will be approximately $99.7, million or approximately $114.8 million if the underwriters’ over-allotment option is exercised in full, the company said.

Proceeds will be used to fund the recent acquisition of properties, including an aggregate of approximately $51.6 million drawn down in June for the acquisition of properties in Eden Prairie, Minn., and Chantilly, Va. Additional proceeds will be used for potential real estate acquisitions, including a portion of the purchase price for a planned acquisition in Falls Church, Va., and other general corporate purposes, the company said.