Small has been beautiful for stock investors over the past year. The large-company S&P 500 index has returned a plump 50% through Tuesday, but its sibling index, the SmallCap 600, has been more generous, returning 64%.

The order of those returns is normal, but the degree of separation is not. Investors have had formal evidence that small companies tend to provide better stock returns than large companies since 1981, when a market cap performance study by Swiss economist Rolf Banz was published in the Journal of Financial Economics. However, the average performance advantage for small-company shares is about two percentage points a year over long time periods, so the 14-point difference over the past year means small fries have been piping hot.

They've also gotten costly. If Wall Street forecasts are to be believed, the SmallCap 600 index trades at 22 times this year's profit, versus 15 times for the 500 index. Cautious stock buyers will want to stick with larger firms, but for daredevils seeking momentum, shares of the three SmallCap 600 members listed below have doubled in price this year.

Ruth's Hospitality Group

Barely a year ago, plenty of investors were wondering if America was slipping into another Great Depression. Steak houses, I'll wager, didn't fare well during the first one, and shares of Ruth's Hospitality Group (RUTH), which owns the Ruth s Chris Steak House chain, plunged below 75 cents apiece in March 2009. Today shares sell for close to $6. The company is best known as Ruth's Chris (so named because an entrepreneur named Ruth bought a New Orleans restaurant called Chris four decades ago), but also operates a fish chain it bought in 2008. Sales including franchise fees fell 15% last year, but the company swung to a small profit from a giant loss after slashing expenses and reducing debt. Analysts expect sales to rebound 1% this year. Shares sell for 20 times this year's forecast profit but just six times peak profits earned in 2006. To investors who foresee a fast return to loose spending, the stock might seem a bargain, but those who remain skeptical might want to skip the steak and opt instead for an investment in cupboard staples like jam and soup.

Quiksilver

Based in Southern California, Quiksilver (ZQK) makes clothing for surfers, skaters and snowboarders, as well as the more inert teens who emulate them. The company has suffered sales declines since fiscal 2007 and it hasn't turned a profit since 2006, but before that, it had produced blazing growth. Quiksilver now owes more than its stock market value, but it's also generating excess cash, and management is using it to slowly improve the balance sheet. The company would likely need a turnaround in sales for the stock to prove a bargain at today's price. Analysts reckon sales at longstanding, company-owned stores in the U.S. have improved in recent months, but that companywide sales will fall another 4.2% this fiscal year ending October, before rebounding 2.5% next year.

Hanmi Financial

Los Angeles-based Hanmi Financial (HAFC) operates a commercial and personal bank and caters largely to California Koreans. Its motto is "Life gets better." Stockholders should hope so; shares plunged from over $20 apiece during 2006, when the recent house bubble peaked, to less than $2 a year ago, but have since climbed past $3. Capital challenges facing the company are "significant and not easily solved," according to Julianna Balicka, who covers the stock for Keefe, Bruyette & Woods, a New York investment bank. In February, the company said it retained Capello Capital as a financial advisor and is "actively exploring all strategic alternatives to satisfy our regulatory orders and meet our business objectives." That could mean Hanmi is looking for a buyer or that it's trying to raise cash through a sale of debt or stock to a deep-pocketed investor. The company says that its chairman has visited potential investors in Korea, including Woori Finance Holdings, but it called reports in the L.A Korean press of a possible sale "filled with inaccuracies."