Morgan Stanley elevated its chief financial officer to a new role as co-chief of investment banking and global securities trading Tuesday as part of a management shake-up ahead of James Gorman's assumption of the CEO role on Jan. 1.

Gorman, who is 51, succeeds John Mack, 65, who will remain as chairman.

Colm Kelleher, who had been chief financial officer, will run Morgan Stanley's institutional securities business along with Paul Taubman, who had been head of investment banking. Kelleher is 52, and Taubman is 48.

With Kelleher moving to a new position, Ruth Porat will take over as chief financial officer. Porat, 52, was previously the global head of Morgan Stanley's financial institutions group.

Morgan Stanley came under criticism earlier in the year for being too conservative in its trading, even as rivals like Goldman Sachs Group Inc. and JPMorgan Chase & Co. used riskier positions to generate huge profits as financial markets rebounded.

Morgan Stanley turned a profit during the third quarter — its first in since 2008 — helped by a comeback in investment banking as more companies resumed issuing debt.

The bank also is benefiting from its recent purchase of a majority stake in the retail brokerage business now known as Morgan Stanley Smith Barney.

Morgan Stanley significantly cut back on its risk taking late last fall at the peak of the credit crisis, when rival investment bank Lehman Brothers collapsed.

The bank diversified its operations, including buying the retail brokerage Smith Barney from Citigroup Inc. It also received a major investment from Japanese bank Mitsubishi UFJ to shore up its balance sheet.

At the end of the third quarter, Kelleher said trading was one area Morgan Stanley had the most room to grow. He'll now be in charge of ensuring that growth.

In other management changes, chief administrative officer Thomas Nides, 48, will take on the additional responsibility of chief operating officer.

Jim Rosenthal, 56, will become chief operating officer of Morgan Stanley Smith Barney and head of corporate strategy for Morgan Stanley. Rosenthal is currently is head of technology and operations companywide.