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.

Stock

1 Month  % Change

CAPS Rating

Genetic Technologies (Nasdaq: GENE) 145.5% *
Orthovita (Nasdaq: VITA) 73.4% ****
International Coal (NYSE: ICO) 35% ****

Source: FinViz.com; One-month % change from April 1 to May 3

While you were out, the market plunged below the 12,000 level, then soared back up. 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
A potential $500 million target market with no direct competitors? I'll take that, and so apparently will Genetic Technologies. The company got approval for a breast cancer test for women at moderate risk of contracting the disease. Its Australian laboratory was approved to manufacture the test, which means it will be able to sell in the U.S. market now.

That ought to be a big step up from Genetic Technologies' current product portfolio, which markets paternity tests and genetic testing for plants, animals, and forensics. Its revenue over the first six months was just $14 million, so this new test has the potential to really boost its results, though management doesn't expect U.S. revenue to really hit the financial statements until the product's second year.

Myriad Genetics (Nasdaq: MYGN) offers genetic tests for the breast-cancer susceptibility genes, BRCA1 and BRCA2. Genetic Technologies is the exclusive licensee of Myriad's BRCA patents in Australia, and a whole lot of litigation has arisen as a result of a court ruling that companies couldn't patent isolated DNA sequences, since they occur in nature.

While the lawsuit is ongoing, highly rated CAPS All-Star member TSIF suggests that Genetic Technologies has some other, more immediate concerns:

Net Income NEGATIVE $7 Million per year, not unusual for a biotech, but with $9 Million in the bank and a long way to go, this spike in share price isn't warranted, especially the last few days. Genetic is now up 10X it's $0.02 per share price in AU.

But you can still keep track of any developments by adding it to your watchlist.

Get some spine
With an offer to buy Orthovita for $316 million, or $3.85 per share -- a 40% premium to where the stock was trading -- Stryker (NYSE: SYK) gets a very complementary addition to its orthobiologics division. In addition to its "bone spackle" Cortoss product, Orthovita also makes Vitagel, which uses collagen, thrombin, and the patient's own plasma to control bleeding.

The common denominator in both products is collagen, which Orthovita previously obtained from Kensey Nash (Nasdaq: KNSY). However, the company recently won approval to manufacture collagen at its own facility. That raised costs for the company, contributing to its loss last quarter; while that loss was narrower year over year, Orthovita's gross margins narrowed, too. The company also makes Vitasure, a plant-based way to stop bleeding.

Although trial lawyers are looking into the acquisition to see whether Orthovita agreed prematurely to the deal, failing to obtain the best value for shareholders, there doesn't seem much of an objection to the merger's completion. Tell us in the comments section below whether Stryker, rather than Orthovita, is a stock you'd consider owning.

Should I stay or go?
International Coal is also jumping in the wake of its own buyout offer. Arch Coal (NYSE: ACI) offered to acquire its rival for $3.4 billion, or $14.60 per share. Once again, questions about the value of the deal arose; at least one shareholder thinks chairman Wilbur Ross is undercutting outside stockholders in a bid to cash out his own investment in the coal miner. Ross brought the company public in 2005, owns about 6% of its shares, and when the deal was announced, he remarked that it "was time to harvest" the money he had put in.

When (or if) the deal gets consummated, the combined company is expected to have total shipments of 179 million tons of coal, generating $4.3 billion in revenue.

CAPS member JSM1213 thought International Coal was one of the best coal mining companies out there. Some 97% of the 856 CAPS members who've rated the company agree that it will outperform the broad market averages. Tell us on the International Coal CAPS page whether you think this deal enriches Wilbur Ross at outside shareholders' expense.

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.

Motley Fool newsletter services have recommended buying shares of Stryker. 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 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.