Sun Life Financial

(SLF) - Get Report

says it's not selling MFS Investment Management, the firm's big mutual fund family.

Last month the Toronto-based insurer said it had hired investment bankers to find a buyer for MFS. But for now, at least, Sun Life says it's holding onto MFS and instead will focus on "improving performance and profit margins'' at MFS.

There had been speculation that both


(WB) - Get Report


Mellon Financial

( MEL) were interested in acquiring MFS, the Boston-based fund family with $168 billion in assets.

Sun Life's decision not to sell MFS could have ramifications for

Marsh & McClennan

(MCC) - Get Report

, the big insurance brokerage that is shopping around Putnam Investments, another Boston-based mutual fund family. Marsh has hired Goldman Sachs to find a possible buyer for Putnam.

Marsh began looking for a buyer for Putnam just days after Sun Life confirmed it wanted to sell MFS.

Both MFS and Putnam were tarnished by the now three-year-old mutual fund trading scandal, and each firm paid hefty fines to regulat