OmniAmerican Bancorp, the Fort Worth-based lender whose stock has more than doubled since going public in 2010, is exploring a sale, two people with knowledge of the matter said.OmniAmerican is working with Sandler O’Neill & Partners to solicit offers, said one of the people, who asked not to be identified because the decision to seek a buyer is confidential. “There would be a healthy list of interested parties for any bank in Texas, especially in metropolitan markets,” said Terry McEvoy, an analyst at Oppenheimer & Co. who covers regional banks. He named BB&T Corp., a North Carolina institution with five Tarrant County branches, including one that opened recently in downtown Fort Worth, and Dallas-based Hilltop Holdings, the parent of PlainsCapital Bank.OmniAmerican, a mutual savings bank, went public in January 2010. It was required to wait three years before soliciting takeover offers.Before converting its charter to a bank in late 2005, OmniAmerican was a credit union. When it decided to sell shares to the public for $10 apiece, it raised $119 million from investors, largely its own customers.The shares (ticker: OABC) rose nearly 3 percent Wednesday to $23.40 on more than 10 times the usual trading volume. At that price, its market capitalization is about $270 millionAt the end of June, OmniAmerican had 15 branches, assets of $1.32 billion and deposits of $818 million, according to a regulatory statement last month. It earned $5.7 million last year.Randi Mitchell, a spokeswoman for OmniAmerican, declined to comment on the potential sale, as did David Franecki, a New York-based spokesman for Sandler O’Neill, which specializes in financial firms. OmniAmerican’s profit fell to $674,000 in the second quarter, down 53 percent from a year earlier, the lender said last month. The bank cited higher provisioning against bad loans and lower yields on interest-earning assets. Since 2007, the bank has been headed by CEO Tim Carter, a longtime Tarrant County banker with JPMorgan Chase and its predecessors. Carter headed the Tarrant County United Way for nearly three years before joining OmniAmerican.OmniAmerican dates to 1956, when it opened as Carswell Federal Credit Union for staff and personnel at the former Carswell Air Force Base in west Fort Worth. It changed its name to OmniAmerican in 1992 to represent its expansion to employees beyond Carswell, which became Naval Air Station Fort Worth Joint Reserve Base in 1994. Staff writer Jim Fuquay contributed to this report.