Spherion Corp. took the biggest gain on the Standard & Poor's SmallCap 600 Index, as markets were lifted ahead of the Federal Reserve's decision on interest rates.
The S&P 600 _ which tracks stocks with a market capitalization between $300 million and $2 billion _ rose 4.44 points, or 1.2 percent, to 379.42.
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.
Shares of Spherion Corp. surged $1.17, or 25.6 percent, to $5.74 after a C.L. King analyst upgraded the recruiting and staffing company to "Strong Buy" from "Neutral."
Regional bank South Financial Group Inc. advanced 51 cents, or 12.9 percent, to $4.45.
Independent Bank Corp., a Midwest regional bank, rose 40 cents, or $10.39 to $4.25.
Among the decliners, LCA Vision Inc. plunged $1.39, or more than a fifth of its value, to $5.21 after the provider of laser-vision correction services said it expected volume to fall 40 percent in the second quarter. Shares hit a five-year low of $4.54 earlier in the session.
Apogee Enterprises tumbled $4.04, or 18.2 percent, to $18.12 after the glass maker said its fiscal first-quarter income fell 13 percent to miss analyst expectations.
Farm machinery maker Lindsay Corp. gave up $7.90, or 8 percent, to $91.40.