S&P SmallCap 600 in Focus: RT COLB

Ruby Tuesday Inc. took the biggest midday gain on the Standard & Poor's SmallCap 600 Index Thursday after the restaurant operator posted a quarterly profit that beat Wall Street estimates, helping pull the index higher.

The S&P 600 rose 3.35 points to 343.47. The index tracks stocks with a market capitalization between $300 million and $2 billion.

Ruby Tuesday shares surged $1.19, or more than a fifth of their value, to $6.49. The company said Wednesday its fiscal fourth-quarter profit came in at 27 cents per share, beating Wall Street estimates.

The company also offered fiscal 2009 guidance largely above analyst expectations.

Shares of Cato Corp. climbed $2.47, or 16.8 percent, to $17.19 after the apparel retailer said its sales at stores open at least a year rose in June and lifted its second-quarter earnings guidance.

Emergency medical transport provider Air Methods Corp. rose $2.74, or 11.2 percent, to $27.27.

Among the decliners, Columbia Banking Inc. plunged $8.25, or 45.2 percent, to $10.04 after the company said it expects to make a provision for loan losses of $15.4 million in the second quarter, prompting at least two analysts to downgrade the stock.

Shares touched a seven-year low of $9.30 earlier in the session.

FirstFed Financial Corp. stock tumbled $1.49, or 21.7 percent, to $5.31.

Zumiez Inc. lost $3.57, or 21 percent, to $13.53 after the sports apparel retailer said its same-store sales fell 3.4 percent in June, missing analyst expectations.

Small-cap companies make up about 3 percent of the total U.S. securities market, but are often cited as good investments due to their low valuations and potential to grow into big-cap stocks.