The head of Alterra Insurance in the US has emerged as a high profile departure in the wake of Markel’s shareholder-approved acquisition of Alterra.According to a report in the Insurance Insider, Doug Worman, CEO of Alterra US Insurance, resigned from the Bermuda-based (re) insurer last week.He is expected to leave at the close of the transaction of the takeover and it is not known if he has a position lined up.Mr Worman joined the company in June 2010. He previously served as managing director of Sharebridge Holdings and president and CEO of Sharebridge Underwriting Group. He spent his earlier career at AIG where he held various underwriting and management positions.Shareholders of both US insurer Markel Corporation and Alterra Capital Holdings Limited last month voted in favour of the $2.98 billion acquisition agreed to by the two boards.The deal is expected to close in the second quarter of 2013.