UPDATE 1-Investor Cerberus open to Deutsche Bank merger with Commerzbank - source

U.S. investor Cerberus is open to a merger between Germany's two largest private banks, Deutsche Bank and Commerzbank, a person familiar with the matter said on Wednesday. Cerberus is a major shareholder in both banks, and its statement is likely to add to speculation of a deal.

"Cerberus wouldn't stand in the way of a merger," said the person familiar with the thinking of the U.S. buyout firm. Cerberus believes there is still room in Germany for two big banks but that it remains an open question whether both can turn around their businesses on their own, the person said.

A spokeswoman for Commerzbank declined to comment. Deutsche Bank didn't immediately respond to requests for comment. (Reporting by Hans Seidenstuecker and Tom Sims; Editing by Thomas Seythal and Mark Potter)