"Culture clashes can be exacerbated by the actions of the acquiring company, particularly when those actions include job cuts," Challenger, Gray & Christmas Inc. said.

The Chicago outplacement consulting firm observed that culture clashes were widespread in the 2001 AOL-Time Warner merger and the 2002 Compaq-Hewlett Packard merger.

Neither of the mergers "lived up to expectations," Challenger said.

In the 2004 Oracle-PeopleSoft merger the clashes were made worse by Oracle Corp. (NASDAQ:ORCL)'s decision to cut 5,000 PeopleSoft jobs.

"Oracle notified workers by Express Mail," Challenger said.

"Cuts can be expected in the News Corp.-Dow Jones merger, as News Corp. seeks to offset its $5 billion purchase," Challenger said.

So far this year, nearly 22,000 merger-related job cuts have been announced, it said.