The world's biggest brokerage has lost team manager Daniel Pace, Patrizia Canziani for the southern Europe division, Olivier Defaux, who priced mortgage investments and Armando La Morgia, who managed analytics.
It is believed to be part of Merrill Lynch's chief executive, John Thain's revolution of the debt business after it was forced to make $8 billion in write-downs on mortgage-related assets.
"It looks like Merrill will have more losses in the first quarter so there should definitely be more cutbacks," Zaheer Ebrahim, at Kennedy Associates, said.
"The asset-backed market and structured credit desks have had a lot of upheaval in the past year so that's one area investment banks, structured investment vehicles and rating agencies will be looking to cut costs in first quarter of 2008."
This news comes after many major banks have made lay-offs, cutting jobs in their asset-backed debt departments.