Bank of America Corp., the third-largest U.S. bank, said yesterday that it plans to cut 30,000 to 35,000 jobs over the next three years because of its acquisition of Merrill Lynch & Co. and the weak economic environment.

The final number of cuts won’t be decided until early next year, the Charlotte, N.C.-based bank said in a statement. The companies together employ 307,000 people, including about 60,000 at New York-based Merrill Lynch. Bank of America spokesman Scott Silvestri said the “vast majority” of job cuts will come next year.

All lines of businesses and staff units will be affected, and “as many reductions as possible” will be made through attrition, Bank of America said. The companies have already begun dismissing equity analysts, according to a person briefed on the changes.

“They are saying that even though we’ve got the best efficiency of any large bank holding company, we still have extra costs,” said Christopher Whalen, managing director of Institutional Risk Analytics, a market-research firm. “They still have to throw more stuff out of the boat because they have to stay afloat.”

Bank of America is the latest firm to announce a work force reduction amid the worst financial crisis since the Great Depression. Citigroup Inc. is planning to eliminate 52,000 jobs in the next year.

The number of job cuts is higher than expected, said Tony Plath, a finance professor at the University of North Carolina at Charlotte.

“This is going to affect the entire bank, not just the investment bank where we knew there would be layoffs,” Plath said.

The company said it continues to lend throughout its product lines and that it is benefiting from a “flight to quality, attracting deposits and new client relationships.” The takeover of Merrill Lynch may be completed this month.

Bank of America took advantage of a crisis in investor confidence at Merrill when the bank agreed to buy the world’s largest securities brokerage in a stock transaction now valued at $19.6 billion.

Whalen said the bank’s efficiency ratio, measuring its costs as a percentage of revenues, is about 43 percent. That compares with 53 percent at JPMorgan Chase & Co., the largest U.S. bank, and 66 percent at Citigroup, the second-largest, he said.

The analysts are being dismissed as the combined company seeks to whittle away overlaps in research. Bank spokeswoman Melissa Kitlowski and Merrill Lynch spokeswoman Susan McCabe Walley declined to say how many analysts will be fired.

Citigroup trimmed the research staff by 3 percent in October and Goldman Sachs Group Inc. fired six equity analysts as it stopped covering 20 stocks and suspended research on 23.