Sears (SHLD) CEO Louis D'Ambrosio announced he was stepping down Tuesday due to a family member's health issues. Chairman and hedge fund billionaire, Edward Lampert will take over as CEO. Shares were down 5% intraday Tuesday. Analysts aren't expecting D'Ambrosio departure to have a major impact on the company. Lampert and his ESL Investments hedge fund have a 55.5% stake in the department store as of Nov. 30, according to Thomson Reuters data. "At