VALLEY FORGE, PA — Vanguard announced that Michael Rollings will join the $3.5 trillion investment management firm next month as chief financial officer and head of its Finance Division. Rollings most recently served as executive vice president and chief financial officer of MassMutual Financial Group. Rollings, 52, will assume leadership of Vanguard’s Finance Division from managing director Glenn Reed, 63, who will remain a member of the firm’s 11-person senior leadership team and head Vanguard’s Strategy Division. Rollings will be responsible for all of Vanguard’s finance functions, including middle-office investment operations, investment product accounting and administration, and internal audit. After starting his career in banking in New York City, Rollings joined MassMutual in 2001 to lead the firm’s Capital Markets division, and was named executive vice president and CFO in 2006.