Lighting equipment maker Acuity Brands Inc. was among the biggest decliners on the Standard & Poor's Smallcap 600 Index after the company forecast a weak environment for the rest of the year, helping tug the index lower at midday Wednesday.
The S&P 600 _ which tracks stocks with a market capitalization between $300 million and $2 billion _ shed 6.42 points, or 1.8 percent, to 359.06.
The biggest decliner was boat retailer Marinemax Inc., which tumbled $1.16, or 17.8 percent, to $5.36.
Shuffle Master Inc. lost 60 cents, or 13 percent, to $4.01 after touching an eight-year low of $3.93 earlier in the session. Shares of Shuffle Master, which sells and leases gaming equipment to casino operators, have declined 28 percent since the company said late Friday it would make a secondary offering of common stock.
Acuity shares tumbled $6.10, or 12.8 percent, to $41.60. The company's third-quarter profit beat estimates but the company forecast weakness in the residential home market and new-store construction would hurt sales.
Among the gainers, regional bank UCBH Holdings Inc. gained 38 cents, or 16.2 percent, to $2.73. A Sandler O'Neill analyst reiterated his "Buy" rating in a note to investors Wednesday after a visit with the bank's management.
Shares of UniFirst Corp. jumped $3.09, or 6.9 percent, to $47.76 after the uniform and protective clothing supplier said its fiscal third-quarter earnings beat analyst estimates thanks to better margins in its laundry business.
Shares of LCA Vision Inc., which provides laser vision correction services, added 26 cents, or 5.6 percent, to $4.90.