Updated from 2:34 p.m. EDT

Shares of

Tween Brands

( TWB) were among the NYSE's biggest losers Wednesday, plummeting 28.5% after the retailer posted lower-than-expected second-quarter results and slashed its full-year outlook.

The company said its income for the second quarter dropped to $2.1 million, or 7 cents a share, from $5.9 million, or 18 cents a share, a year earlier. Analysts expected earnings of 15 cents a share.

Tween Brands blamed the shortfall on a later back-to-school season, a shift in the timing of state sales tax breaks and a decline in traffic. For the full year, the company now sees earnings of $1.80 to $1.95 a share, below its prior guidance of $2.10 to $2.25. Shares closed down $11 to $27.59.

Fellow retailer

Charming Shoppes

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slipped 1.6% after the company offered a third-quarter forecast that was short of Wall Street's estimate. The company, owner of brands like Fashion Bug and Lane Bryant, posted a second-quarter profit of $18.3 million, or 14 cents a share. That was better than Wall Street's expectation for a profit of 12 cents a share, but below Charming Shoppes' original forecast.

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For the third quarter, the company sees earnings of 11 cents to 13 cents a share, compared with analysts' average target of 15 cents. Shares closed down 15 cents to $8.99.

Among the winners,

MGM Mirage

(MGM) - Get MGM Resorts International (MGM) Report

jumped 8.9% Wednesday after the investing arm of the Dubai government announced plans to invest $5 billion in the casino operator. Dubai World will buy a 50% stake in MGM's CityCenter development in Las Vegas, and will buy up to $2.4 billion of the company's stock at $84 a share. Shares of MGM closed up $6.62 to $80.94.

Shares of

Nymex Holdings

( NMX) leaped 6.1% after the commodities and options exchange owner said it has held talks about a potential merger. The company called the discussions preliminary and didn't name its potential partner. Shares closed up $7.28 to $126.06.

Toll Brothers

(TOL) - Get Toll Brothers, Inc. Report

was up 5% after the homebuilder's third-quarter results weren't as bad as expected. The company earned $26 million, or 16 cents a share, for the quarter ended July 31, including $147 million worth of pretax writedowns and a $15 million pretax gain. Excluding the items, the company still recorded a profit, besting analysts' expectation for a 2-cent-a-share loss. The stock closed up $1.06 to $22.15.