Morgan Stanley, the sixth-largest U.S. bank by assets, plans to eliminate about 1,600 jobs from its investment bank and support staff in coming weeks, a person familiar with the matter said.

The cuts total about 6 percent of the New York-based company’s institutional securities group, which includes investment banking and trading units, and support staff, the person said, asking not to be identified because the decision hasn’t been made public. About half the reductions will be in the U.S., the person said.

Morgan Stanley dropped about 4,200 employees in the first nine months of last year through job cuts and unit sales, after saying in December 2011 it would eliminate 1,600 jobs. Chief Executive Officer James Gorman, 54, has pledged to reduce costs as return on equity remains below the bank’s cost of capital.

All levels of employees will be affected, and some workers have already been notified, the person said. Morgan Stanley has laid out a plan to cut $1.4 billion of annual expenses by next year.

Morgan Stanley fell 5 cents to $19.60 at 11:04 a.m. in New York. The shares climbed 26 percent in 2012, and trade at about 65 percent of the firm’s book value.

Citigroup Inc. said last month it would cut 11,000 jobs and pull back from some emerging-market nations. UBS AG announced in October that it would fire 10,000 workers and largely exit fixed-income trading.