Flagstone Reinsurance Holdings announced that it will issue a quarterly dividend of four cents per common share.The dividend is payable on September 15, 2012 to shareholders of record at the close of business on September 3, 2012. As September 3 falls on an Exchange holiday, the effective record date for the dividend will be the close of business on August 31, 2012.The Bermuda Class of 2005 reinsurer, now domiciled in Luxembourg, reported a second quarter profit of $13.5 million.