With its Fourth acquisition in less than two years – that of National City Corp. for $5.2 billion - PNC Financial Services Group Inc. has become the country’s fifth largest bank as measured by deposits. Founded in 1845, National City Corp. in the last two years went from being highly profitable to being a troubled institution.

The sale culminates amid the nation’s credit crunch and troubled mortgage market. National City had tied its future largely to mortgages, many which were sought by brokers in deals that proved to be high-risk.

Pittsburgh-based PNC, led by Chief Executive Officer James Rohr, announced the deal yesterday after getting $7.7 billion in government funds, part of the $125 billion the Treasury is distributing to regional banks to thaw frozen credit markets.

Taking advantage of a weaker rival, Rohr, 60, is all set to expand his reach into the Midwestern U.S. The acquisition, expected to be completed by December 31, will bring PNC to more than 2,500 branches in 13 states and Washington, D.C.

PNC expects about $20 billion in losses from National City’s lending portfolios, or almost 18 percent of the total. It anticipates $2.3 billion in merger-related charges and will cut $1.2 billion in costs in the combined bank.

Commenting on the news of acquisition, Jackson, who spoke with leaders of National City and PNC said: “This news, even though disappointing, was known to be a possibility really based on the financial and economic crisis not only in the United States but throughout the world.”