Nov. 26 (Bloomberg) -- JPMorgan Chase & Co., the third- largest U.S. bank, named Barry Zubrow chief risk officer as the value of Wall Street firms' investments in subprime mortgages and related bonds tumbles amid credit-market turmoil.

Zubrow, who fills a position left vacant when Don Wilson retired about a year ago, joins the New York-based bank from investment management firm ITB LLC, JPMorgan said in a statement today. Zubrow, 54, an adviser to his former Goldman Sachs Group Inc. colleague, New Jersey Governor Jon Corzine, will report to Chief Executive Officer Jamie Dimon.

``The chief risk officer function is a critical role for our company,'' Dimon said in the statement.

JPMorgan fell $1.49, or 3.6 percent, to $40.46 at 4:25 p.m. in New York Stock Exchange composite trading. The stock has dropped 16 percent this year compared with a 25 percent decline in the 24-member KBW Bank Index.

Analysts predict that writedowns tied to losses on subprime mortgages by banks and securities firms, already $50 billion worldwide, will continue to grow. Fallout from bad mortgages has toppled half a dozen hedge funds and the chief executive officers at three of the world's biggest financial companies, Citigroup Inc., Merrill Lynch & Co. and UBS AG.

Citigroup Management Change

Citigroup, the largest U.S. bank, named Jorge Bermudez to replace David Bushnell as chief risk officer Nov. 16 after the company said as much as $11 billion in writedowns on mortgage- related investments may lead to the New York-based lender's first quarterly loss since at least 1998. On Nov. 19, Goldman Sachs analyst William F. Tanona downgraded Citigroup to ``sell'' from ``neutral,'' predicting that the lender's writedowns of collateralized debt obligations, securities backed by pools of bonds, may total $15 billion over the next two quarters.

JPMorgan marked down the value of CDOs by $339 million in the third quarter. The bank had about $1.5 billion in CDO exposure in its trading business, little of it tied to subprime mortgages, Dimon said earlier this month.

Zubrow worked at Goldman Sachs from 1979 to 2004, JPMorgan said. His last job before leaving the firm where Corzine was co- chairman until 1999 was chief administrative officer. Zubrow will also join JPMorgan's operating committee.

To contact the reporter on this story: Elizabeth Hester in New York at ehester@bloomberg.net.

Last Updated: November 26, 2007 16:38 EST