Mark W. Callahan has been an Executive Vice President at HCC Insurance Holdings Inc., since August 9, 2010 and served as its Chief Underwriting Officer from March 2011 to March 2013. Mr. Callahan served as Chief Actuarial Officer at HCC Insurance Holdings Inc., since August 9, 2010 until March 2011. Mr. Callahan served as Chief Actuarial Officer at XL Insurance (Bermuda) Ltd. He served as Chief Actuarial Officer of Insurance Operations at XL Group plc (formerly, XL Capital Ltd.) since September 14, 2004. He served as Senior Underwriter for the alternative risk transfer unit, XL Financial Solutions. Mr. Callahan joined XL in 1998, before which he had worked for Milliman in the US, where he was responsible for establishing and managing its property/casualty office in Dallas and later managing its Bermuda office. Mr. Callahan is a Fellow of the Casualty Actuarial Society and holds a BBA in Accounting from the University of Texas at Austin.