Marsh & McLennan (MMC) has reportedly attracted a field of private equity buyers for its corporate investigations unit Kroll with a price tag of $US1.3 billion ($1.4 billion).

MMC bought Kroll for $US1.9 billion ($2.1 billion) in 2004 from founder Jules Kroll as a value-add for clients at the top end of the global corporate market.

But the hoped-for synergy has not been there, and parts of Kroll have been offloaded after a $US425 million ($465 million) writedown in 2008 dragged the parent company into a $US210 million ($230 million) first-quarter loss.