Colonial Bank (CNB) might have represented a failed strategy, but to BB&T Corp. (BBT), the closed lender now stands as a nearly ideal fit for its plan to become a much larger bank.

Support from the Federal Deposit Insurance Corp. leaves BB&T with "minimal risk" for the troubled loan book that brought Colonial down. And Colonial had what BB&T wants: Branches in attractive markets.

"This deal is definitely very strategically compelling to us because it increases us to No. 5 [in deposit market share] in Florida and gets us into a new market, in Alabama," where Colonial was the fourth largest bank, said Daryl N. Bible, the chief financial officer of BB&T in an interview.

The purchase is financially compelling because of the loss-sharing agreement with the FDIC and because the purchase is immediately accretive, Bible said.

BB&T will get 356 branches and about $20 billion of deposits. It will also purchase $22 billion in assets, and the Federal Deposit Insurance Corp. agreed to a loss sharing agreement with BB&T for $15 billion of Colonial's assets. BB&T has $152 billion in assets and $102 billion in deposits.

The Alabama State Banking Department closed Colonial BancGroup late Friday, ending a long struggle by the Alabama bank. It continued to make loans to real estate developers long after the crisis started and others pulled back. It ultimately failed to find investors willing to provide the capital needed to allow Colonial to continue.

The FDIC took over as receiver and estimates that the failure of Colonial will cost its Deposit Insurance Fund $2.8 billion, less than the FDIC said it had projected.

For BB&T, the deal came together fast. The FDIC agreed to the sale of Colonial Bank late Thursday; it was the "least costly" resolution for the FDIC, the agency said.

Bible said BB&T was one of four parties interested in the bank, but in the end one other firm remained in the run. "This was a very competitive process," he said, and said it is his understanding that BB&T bid against a "big, strong, sophisticated bank."

"We have a very strong indemnification from the government" that will protect BB&T from the legal risk stemming from a criminal investigation into Colonial by the Department of Justice, and other legal trouble. "The legal risk does not come with this transaction."

Colonial had tried to sell branches in Nevada, and Bible said that contract is void. The acquisition also gives BB&T a foothold in Texas, a market many analysts and bankers consider one of the nation's most attractive and one that is holding up better in this crisis than most. Asked whether BB&T intends to expand there, Bible said, "We are evaluating both Texas and Nevada and will decide at some point what we are going to do with those."

Florida, meanwhile remains "a market that is stressed, but we have very conservative underwriting and we are still one of the strongest financial institutions in the country; we know how to operate, we know the markets," Bible said.

Colonial will offer cost-saving opportunities, and Bible said BB&T will provide investors with specifics on Monday. He did say, however, that a "limited number" of branches will be closed; he didn't identify where.

He expects "some attrition" at Colonial, which had paid high interest rates on deposits to help its weakening capital base, but Bible said BB&T itself is taking market share from its competitors.

BB&T, an active and experienced acquires, has long held aspirations of growing to become a much larger bank - it considered mergers of equals, but nothing came of it. Bible said Friday the bank, for now, "will focus solely on...integrating this acquisition."

Colonial is a sizable purchase with all the integration risk that comes with folding an acquisition into existing operations. But Bible noted that BB&T has done deals similar in scope relative to its much smaller asset size years ago.

Systems may take about a year to convert, but changing Colonial's culture to BB&T's might take as much as three years, Bible said. BB&T has created a strong corporate identity around the values of its chairman, John Allison, who was an outspoken opponent of the government's early intervention into the financial crisis.

Bible said BB&T puts much emphasis selling a much broader array of financial products and services. "We want to have time to train people," he said.

-By Matthias Rieker, Dow Jones Newswires; 212-416-2471; matthias.rieker@dowjones.com