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 regional bank S&T Bancorp (Nasdaq: STBA) have plunged today by as much as 10% after the company reported earnings far short of expectations.

So what: The bank put up earnings per share of just $0.12, which hardly compares to the $0.39 that the Street was expecting. The results were hurt by one-time merger expenses related to its recently completed merger with Mainline Bancorp.

Now what: CEO Todd Brice said the company just made various moves to position itself for future growth, including another merger that was recently announced to acquire Gateway Bank of Pennsylvania. That deal is expected to close in the third quarter, which should allow S&T to expand into Pittsburgh suburbs.

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