TORONTO — New Jersey-based Commerce Bancorp, for years one of the fastest growing banks, is being bought by Toronto-Dominion (TD) Bank for $8.5 billion.

Commerce burst on the banking scene with an almost McDonald's approach of having lots of branches and providing quick, convenient service. Rarely a leader in rates, it still was one of the country's fastest growing banks. It ran into some trouble earlier this year when its CEO, Vernon Hill, left the bank following probes into insider deals.

This deal basically doubles TD Bank's footprint in the U.S. "As customer needs grow more similar regardless of location and businesses are growing more global, foreign banks (especially Canadian banks) are looking to expand their presence into the U.S. Banks are especially targeting business customers who offer a high potential for cross-selling and generating fee-based revenues," said Christine Barry, research director for Aite Group.