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 health-care service provider Amerigroup (NYSE: AGP) had a solid day today, rising as much as 10% before closing with a 6.8% gain.

So what: The bad news for Amerigroup shareholders is that earnings per share in the first quarter fell 53% from last year. The good news is that the drop was fully expected and the $0.64 per-share profit was a good deal better than the $0.56 that Wall Street analysts had estimated. Revenue grew 15% year over year to $1.77 billion, which was slightly short of the $1.81 billion that analysts were looking for.

Now what: There wasn't much of an update on the company's full-year outlook -- revenue is still expected to climb 40%, and the net margin is still seen in the 1.5% to 2.5% range. However, the company did tighten the expected health benefit ratio for the year, bringing it down slightly to a midpoint of 86.2%.

In all, it looks like a solid quarter for Amerigroup, and the company's expansion efforts in Texas and Louisiana should help set it up to deliver on the growth promises for the full year.

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