Chammah also expected more banks to fall victim to the crisis, the paper said.

"We will likely see more insolvencies among small U.S. regional banks that have focused on mortgage business," the paper quoted him as saying.

Chammah also said return-on-equity rates of 25 percent were a thing of the past for the investment banking industry, the paper reported.

"I estimate returns in the industry will be more like 15 to 20 percent as a rule," the paper quoted him as saying.

(Reporting by James Regan; editing by Rory Channing)