Resist the urge to high-five everyone in the cubicles next to you. Your stock may have just strapped on a rocket pack and taken off for the moon, but smart investors won't celebrate until they know that upward leap was justified. Without a fundamental basis for the bounce, these stocks can quickly make the return trip down.

Is now the time to lock in profits, or is this just the first step toward even higher valuations down the road? Let's examine several stocks that just hit the afterburners, and see whether they're truly headed into orbit.

Stock

CAPS Rating
(out of 5)

Yesterday's Change

Amarin (Nasdaq: AMRN)

**

95%

A123 Systems (Nasdaq: AONE)

***

11.3%

Identive Group (Nasdaq: INVE)

*

11.3%

The decision by Standard & Poor's to revise the country's debt down from stable to negative rattled the markets. Stocks dropped 140 points on the news, or 1.4% -- so stocks that went significantly higher are pretty big deals.

New frontiers in investing
Amarin is working hard to prove that it's not trying to sell you snake oil. Its triglyceride lowering fish oil candidate AMR101 landed another big test when its Anchor clinical trials showed it significantly lowered triglyceride levels without raising "bad" LDL cholesterol, while meeting all of its endpoints for safety.

Those are key differentiators from similar treatments from GlaxoSmithKline whose Lovaza can raise "bad" cholesterol in some patients, yet still brought in almost a billion dollars worth of sales last year.

Last month there was speculation that someone like Glaxo or Pfizer (NYSE: PFE) might want to reel Amarin in as an acquisition, though the latter's decision to cut back its shopping list fueled a bit of a slide in Amarin's stock. Since the fall had been precipitated by a lack of news, and the prospects for the Anchor trial looked promising, I thought it represented an opportunity for investors to hook the stock for their portfolio.

Apparently a lot of CAPS members thought so too as 86% of those rating the biotech believed it would outperform the market. You can let us know on the Amarin CAPS page or in the comments section below whether this still has potential or there are larger fish to fry now.

Not an uncommon occurrence
You can't argue with CAPS member buffalonate's timing. A week ago he said it was time to buy lithium-ion battery maker A123 Systems because of expectations it would double revenues over the next two years and the Energy Department was helping to finance the construction of a new manufacturing facility.

They probably won't be profitable until 2013 but they have doubled capacity in the last year and I can't imagine that they would do that if they didn't see the product being economically viable in the near future. They recently announced in their quarterly report that they will be supplying batteries for a start-stop hybrid system for one of the big three auto companies in 2013.

Goldman Sachs apparently agrees because it upgraded the stock yesterday, citing the market's myopia to only one part of the story. Pulling back the lends a bit gave you a clearer picture there's a reason to be charged up about its future.

A123's numbers look a lot more realistic than those being offered by Chinese battery maker Advanced Battery Technologies (Nasdaq: ABAT), which stands accused of just making stuff up about revenues, profits, and orders.

You can watch the drama play out by adding the battery maker to your watchlist and charging up the discussion on the A123 Systems CAPS page.

Making a connection
Near field communications, or NFC, could be a huge opportunity in the future as it allows communication over very short distances, typically just a few centimeters. Credit cards are looking to use the technology as the market researchers at Strategy Analytics think it could mushroom into a $36 billion industry.

But there are a lot of other uses for the technology and Identive Group is partnering with Google (Nasdaq: GOOG) to test a system in Austin, Texas, to enhance the search engine's Place Pages service. Local businesses will affix an NFC tag on their business windows and consumers will be encouraged to use a downloaded app to rate the businesses on their Place pages. It's a very small test of the concept, but one with huge implications. It was also the reason Indentive's stock exploded the other day when it sent out a press release about it.

While the stock quickly gave up most of those gains -- no doubt investors realized just how small the test was -- Identive has now reached the radar of a lot more people. So when Identive subsidiary SCM Microsystems sent out a blurb that it was received its first orders for terminals to help implement Germany's eHealth card program, the stock bounced up again.

Only a handful of CAPS members have picked up on the stock so far, and all five All-Stars marked it to outperform, no doubt immediately understanding the market's crazy movement on the Google press release. NFC will be a big deal, and Dolby Labs (NYSE: DLB) is even moving to create a patent pool for NFC players, but right now it's still pretty much in its infancy and Identive's role is a small one.

But you can stay on top of the company's developments by adding the stock to the Fool's free portfolio tracker.

Going into orbit
That's why it pays to start your own research on these stocks on Motley Fool CAPS, where you can read a company's financial reports, scrutinize key data and charts, and examine the comments your fellow investors have made, all from the stock's CAPS page. Then you can decide for yourself whether your stock's headed for reentry, or off to infinity and beyond.

Google and Pfizer are Motley Fool Inside Value picks. Google is a Motley Fool Rule Breakers recommendation. Dolby Laboratories is a Motley Fool Stock Advisor selection. GlaxoSmithKline is a Motley Fool Global Gains pick. The Fool owns shares of GlaxoSmithKline and Google. 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.

Fool contributor Rich Duprey owns shares of Dolby but does not have a financial position in any of the other stocks mentioned in this article. You can see his holdings here. The Motley Fool has a disclosure policy.