McCormick, who had previously been under consideration to be Treasury Secretary, declined partly because he is happy with his job at Bridgewater and the government role was not the right fit, said the person, who requested anonymity because the information is private.
Westport, Connecticut-based Bridgewater declined to comment. McCormick did not immediately respond to an email seeking comment. The news of his withdrawal was first reported by Bloomberg.
The Washington Post said the Trump team was considering keeping the current deputy defense secretary, Robert Work, on for at least several months.