Two banks seen as acquisition targets agreed to combine Monday morning.

M&T Bank Corp., the Buffalo, N.Y.-based bank holding company, and Wilmington Trust Corp. announced a definitive agreement under which the Wilmington-based firm will merge into M&T in a stock transaction valued at $351 million.

M&T is the bigger of the two with assets of $68.2 billion. Wilmington Trust, founded by the DuPont family, has $10.4 billion.

Deal would close in mid-2011. Here's a link to the joint news release.

Wilmington Trust had reported unexpected losses in recent quarters, while M&T saw its major shareholder Allied Irish Banks announce plans to sell its 22.4 percent stake last month.