Cap Markets

Atlantic Capital Bancshares in Atlanta plans to issue $50 million in subordinated debt to finance its acquisition of First Security Group in Tennessee.

The $3.4 billion-asset company plans to use the proceeds for general corporate purposes, possible acquisitions and capital investments in Bridgehampton National Bank.

CircleBack Lending, a Boca Raton, Fla., marketplace lender, has completed a $17.4 million round of equity financing.

PSB Holdings in Putnam, Conn., plans to convert from mutual ownership to a stock-owned bank.

Orchard Platform, which provides services to institutional investors in the marketplace lending industry, has raised $30 million in additional funding.

Bridgewater Bancshares in Bloomington, Minn., has raised $15 million from the private-equity firm Castle Creek Capital.

Summit State Bank in Santa Rosa, Calif., has exited the Small Business Lending Fund.

Pacific Mercantile Bancorp in Costa Mesa, Calif., has reached an agreement to swap about 3 million shares of common stock for all of its outstanding preferred stock and warrants.

Colony Bankcorp in Fitzgerald, Ga., has redeemed about 17% of its Troubled Asset Relief Program preferred shares for about $4.3 million.

Northwest Bancorp. in Spokane has raised $20 million from a private placement of common stock. Northwest plans to use some of the proceeds to complete its acquisition of Fairfield Financial Holdings, which was announced in late June.