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 Gain Capital Holdings (NYSE:GCAP) were trading nearly 17% lower Friday after the company reported disappointing first-quarter earnings last night.

So what: Gain reported revenue of $75.8 million -- a 52% year-over-year improvement -- and earnings of $0.08 per share for its first quarter. However, optimistic Wall Street analysts had been looking for $86.8 million in revenue and $0.20 in EPS, so this was not only a double whiff, but an ugly double whiff for the online trading services provider. For comparison, Gain's EPS was $0.11 in the year-ago quarter. 

Now what: Gain has only been publicly traded since the end of 2010, but it's been a very volatile stock over its brief life on the markets -- shares fell to half their post-IPO price by the start of 2013, only to triple in the first 10 months of that year before plunging again. This is despite the fact that Gain's EPS has actually grown more than its share price since the start of 2012, and has been on a consistent and powerful upward trajectory since 2013 -- until today, at least. Despite (or because of) this whiff, Gain's P/E is barely in double-digit territory, which is its lowest in over a year, and its forward P/E is only 6.8. A 2% dividend yield also appears to be sustainable, so you may want to do a little digging -- this on-sale stock might be a good addition to a growth portfolio.

Alex Planes has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.