ASGN Inc. in Calabasas has acquired Boston consulting firm Leapfrog Systems Inc. for up to $72 million, the company announced Tuesday. Leapfrog delivers enterprise-level IT transformations based for Fortune 500 clients. It will become part of ASGN’s Apex Systems division, a staffing firm in Glen Allen, Va., but will retain its presence in Boston. ASGN Chief Executive Ted Hanson said in a statement the acquisition will help Apex capture more commercial consulting opportunities, especially from clients in the financial services, insurance and health care sectors. “We have been witnessing an accelerating trend toward digital transformation, making now the ideal time to welcome LeapFrog to ASGN,” he added. Along with the cash component, ASGN is granting inducement stock awards to 14 LeapFrog employees, covering a total of about 42,000 shares. Shares of ASGN (ASGN) closed Tuesday up $1.30, or about 2 percent, at $73.19 on the New York Stock Exchange.