Some stocks are one-hit wonders, making a big splash when they first appear, then quickly fizzling into obscurity or oblivion. But for other stocks, that initial big move is only a preview for even bigger and better gains to come.

Today, we've listed three stocks that made some of the biggest upward moves over the past month, which we'll pair with the ratings issued by our Motley Fool CAPS community. The higher each stock's rating, the greater CAPS members' faith in that company's ability to keep on beating the market.


1 Month % Change

CAPS Rating

Gerdau Ameristeel (NYSE: GNA)



Vaalco Energy (NYSE: EGY)



Arrowhead Research (Nasdaq: ARWR)



1 Month % change from May 10 to June 9.

As the markets whipsaw to changes in consumer sentiment, there will be weeks like this one, where it's hard to believe anyone recorded a positive performance. So before we get shaken out again, let's see why the CAPS community thinks some of these companies might continue to outperform the market.

A mighty temblor
It was just earlier this year that Gerdau Ameristeel was rumored to be a potential suitor for Commercial Metals (NYSE: CMC) as steel industry titans began to tie up in deals to bolster their finances. Nucor (NYSE: NUE) joined with Japanese conglomerate Mitsui in a joint venture while AK Steel (NYSE: AKS) looked like it might be taken out, too.

As it turns out, Ameristeel's Brazilian parent, Gerdau, says it's going to buy up the remaining 33% stake it doesn't already own and roll the company back into its fold. The $1.6 billion bid is a 53% premium to the price Ameristeel was trading at before the announcement, and underscores the bullish sentiment investors had for the mini-mill steel producer. More than 96% of the CAPS member rating Gerdau Ameristeel indicated they believed it would outperform the broad market averages.

Gerdau has a similarly bullish profile, and CAPS member Simbalion200 doesn't see a reason for the sentiment to change for the steelmaker:

One of the more profitable companies in the Iron and Steel industry with a net margin of 3.78%. Revenue is increasing. 46.66% increase in earnings. Company has improved earnings per share by 46.7% in the most recent quarter compared to the same quarter a year ago. Stock price has surged by 177% and I see no reason why this should not continue.

A slick opportunity
The broad brush the market painted oil and gas drillers in the aftermath of the BP (NYSE: BP) Gulf of Mexico disaster was evident in the price action on VAALCO Energy's stock. In the early weeks following the explosion and the subsequent moratorium imposed on offshore drilling, VAALCO's stock dropped along with everyone else's in the industry. Yet the oil and gas exploration company has sparse assets in the Gulf of Mexico, as most of its operations are located in Gabon and Angola in East Africa.

Over the past month, VAALCO's shares have rebounded, rising nearly 25% as it became apparent it wasn't going to be affected by the calamity. Astute investors who saw that when it came to VAALCO, it was much ado about nothing, find themselves sitting on a tidy profit.

CAPS members have remained consistently upbeat about the driller's prospects, with 97% of the more than 1,500 members rating it believing it will outperform the market. Drill down into its growth prospects on the VAALCO Energy CAPS page and let us know whether you agree it's likely to remain a gusher.

Still feeling the aftershocks
It was a passel of good news that propelled nanotech outfit Arrowhead Research higher over the past two months. After receiving notice from the Nasdaq exchange that it had regained compliance in April, Arrowhead reported a 33% increase in revenues (when you back out grants it received last year but were not repeated this time around) and announced that its subsidiaries entered into several agreements to commercialize various technologies. One would develop carbon nanotube-based displays and solar cells, while the other would seek to accelerate the commercialization of a multi-stage drug delivery platform to improve the effectiveness of drug therapy, particularly for cancer.

Arrowhead is flying under the radar of most of Wall Street, with only one analyst covering the nanotech researcher these days, but CAPS is starting to take notice, and more than 110 members have weighed in on it (97% think it will outperform). You can join them on the Arrowhead Research CAPS page and tell us whether there are big things in the future from this small-cap stock.

Shake, rattle, and roll
With these stocks shaking the market this past month, it pays to start your own research on them at Motley Fool CAPS. Read a company's financial reports, scrutinize key data and charts, and examine the comments your fellow investors have made -- all from a stock's CAPS page.

Nucor is a Motley Fool Stock Advisor selection. Try any of our Foolish newsletter services today, free for 30 days.

Fool contributor Rich Duprey does not have a financial position in any of the stocks mentioned in this article. You can see his holdings here. You can shake, rattle, and roll The Motley Fool's disclosure policy, but it still won't break.