Bank of America Corp. estimated it will reduce its work force by 30,000 to 35,000 over the next three years, reflecting redundancies from the acquisition of Merrill Lynch & Co. and the weak global economy.

The cuts would represent about 9% to 10.5% of the combined companies' work force.

Shareholders of both companies approved the $16.5 billion transaction last week, clearing the way for it to be complete at the beginning of next year. The deal, which rescued Merrill when it was teetering from the financial crisis, will give Bank of America the world's largest wealth-management business, with nearly 20,000 financial advisers and $2.5 trillion in client assets.

Noting that it won't determine a final tally for the job cuts until early 2009, the banking giant said the reductions will come from both companies and all lines of business. However, Bank of America hasn't determined the geographical locations of the cuts.

The company plans to reduce as many of the jobs as possible by attrition. However, earlier Thursday, the two companies began laying off workers in their equity-research departments in an effort to end duplicate coverage and not confuse clients, according to sources at the companies.

Shares rose 1.7% to $15.16 in after-hours trading.

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