Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Delaware trust bank Wilmington Trust (NYSE: WL) dove 44% in intraday trading as the bank announced that it's selling itself to M&T Bank (NYSE: MTB) for roughly $3.84 per share.

So what: Just last week I had my eye on Wilmington as investors considered the potential for a buyout. At that point I said, "true-blue investors had better make sure there's something other than a train at the other end of Wilmington's current tunnel." Looking at Wilmington's third-quarter results -- which were also released today -- it appears that it was, in fact, a train coming right at investors. The bank's total nonperforming assets jumped 77% since last quarter, and loan-loss provisions were boosted 37%.

Now what: It's been reported that the sale process for Wilmington included other potential acquirers and investors, including Bank of Montreal (NYSE: BMO), Toronto-Dominion Bank (NYSE: TD), and some private-equity players, so it seems relatively unlikely that a higher offer will come to the table for Wilmington. On the flip side of this massacre, it seems like this could be a positive for M&T shareholders. M&T will have its work cut out trying to get Wilmington's loan book under control, but will get $8.3 billion in deposits and a well-known name in the trust business.

Interested in more info on Wilmington Trust? Add it to your watchlist here by clicking here.

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Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy assures you no Wookiees were harmed in the making of this article.