BofA to acquire ABN unit

Bank of America Corp. agreed to buy Dutch bank ABN Amro Holding’s U.S. unit, LaSalle Bank Corp., for about $21 billion, making it the largest bank in Chicago, a person with direct knowledge of the situation said.

The purchase would fill one of the few remaining holes in Bank of America’s sprawling branch network, the nation’s most extensive.

The Dutch bank has been in exclusive talks to be acquired for an estimated $80 billion by London-based Barclays, and the Wall Street Journal reported that a deal may be announced as early as today. Selling LaSalle would reduce the purchase price for Barclays and increase the unit’s value by putting it in the hands of a determined buyer.

The purchase, which may be subject to regulatory approval, will satisfy a goal for Chief Executive Kenneth Lewis by vaulting Bank of America ahead of JPMorgan Chase & Co. in the third-largest U.S. city.

Although Bank of America has been opening branches there since 2003, Chicago is the only major U.S. financial center in which the bank does not rank among the top five lenders by deposits.

Bank of America, the nation’s second-largest bank by assets, operates more than 5,700 branches.