NEW YORK (AP) — PNC Financial said it plans to buy Colorado-based FirstBank for $4.1 billion, giving PNC a substantial presence in the Colorado banking market as well as Arizona.

Based in Lakewood, Colo., FirstBank, which is typically branded as 1stBank, is a midsized bank that operates 120 retail branches with roughly $26 billion in assets. The bank is privately held, but the banks disclosed that the stockholders of FirstBank, who collectively own 45.7 percent of the shares, already have voted in favor of the merger.

PNC has been on an acquisition streak in the last few years to made the Pennsylvania-based bank one of the biggest players in retail banking in the country. PNC bought the American operations of Spanish bank BBVA shortly a few years ago.

The FirstBank acquisition will make PNC the largest bank in the Denver market, and will give PNC more than 70 branches in Arizona. PNC also will grow to approximately $575 billion in assets.