New York hedge fund DB Zwirn & Co is winding down its principal funds after investors – rattled by lapses in internal controls, including the expense of a private jet used by the firm’s founder – said they would withdraw more than $2bn.

Investors started pulling their money after the group, which has almost $5bn under management, disclosed in March last year that an independent internal review had uncovered improper transfers among funds and improper handling of operational expenses.