J.F. Lehman & Company, a mid-market private equity firm focused on the defense, aerospace and maritime sectors, has promoted four employees. The changes are as follows: Lisa M. Steffens will become managing director of fund finance and investor relations; David L. Rattner will become managing director, legal, administration and compliance; William J. Hanenberg will become vice president; and David F. Thomas will become senior associate. J.F. Lehman & Company has offices in New York and Washington, D.C.