Retail Winners & Losers: Rite Aid, Sears

NEW YORK(TheStreet) -- It's witching day in the market, and the retail sector is not immune from the day's mythical volatility.

The S&P Retail Index was up 1% to 386.05 and shares of companies within the sector saw some big movements.

Witching day happens once each quarter and is the day on when four contracts expire: stock-index futures, stock-index options, stock options and single-stock futures. Such multi-expirations are known to cause volatility.

One of the biggest retail gainers is sports-apparel store Zumiez(ZUMZ Quote), which soared 10.5% to $16.96. The specialty retailer was upgraded to neutral from underperform by an analyst at Wedbush Morgan.

"We believe Zumiez benefited from solid back-to-school selling during the Labor Day weekend, and while there may be some deceleration in the latter half of the month, we believe September sales will once again demonstrate an improvement from year-to-date trends," analyst Betty Chen wrote in a client note.

Sears(SHLD Quote) also climbed 4% to $68.50 after it announced it has launched its own third-party market place. Wal-Mart Stores(WMT Quote) also rolled out this feature earlier in the month.

GameStop(GME Quote) leveled up 2.5% to $26.48 in afternoon trading, as noise grows that video game sales could shape up during the holidays.

Rumors have been circulating that Nintendo's Wii could even see a price cut, following price cuts for Sony's(SNE Quote) PlayStation and Microsoft's(MSFT Quote) Xbox 360.