MCLEAN, Va. – Richard Syron, a former American Stock Exchange chairman was chosen by Freddie Mac as its new chief executive officer. Syron becomes the third CEO Freddie Mac has had since June when the government sponsored enterprise went through a management shakeup as a result of circumstances surrounding three-years' worth of accounting errors that caused the company to understate its profitability by $5 billion and forced it to recently announce its restated earnings. Syron replaces Gregory Parseghian, former executive vice president-single family, who was elected president/CEO of Freddie Mac by the company's board and replaced ousted chairman and CEO Leland Brendsel. Parseghian was forced from the position by federal regulators after it was determined he was too closely tied to the accounting problems. Syron headed the American Stock Exchange from 1994 to 1999. He's also held executive positions at the Federal Reserve Bank of Boston and the Federal Home Loan Bank of Boston.