Denny's ( DENN) shares gained Friday after the Spartanburg, S.C.-based restaurant chain operator said same-store sales in August increased 4.1%. The average customer check increased 3.6% during August. Year-to-date same-store sales are up 2.5%, while the average customer check increased 5.4%. Shares were trading up 21 cents, or 6.3%, to $3.56.

Nam Tai ( NTE) plummeted after the Vancouver, B.C.-based contract electronics manufacturer slashed its financial guidance, saying tough competition is pressuring sales and margins. The company expects those conditions to hurt numbers in the third and fourth quarters -- and into 2007 and 2008. Nam Tai said it expects to post 10% sales growth for 2006 and 12% in both 2007 and 2008. The company had earlier forecast 25% growth for each year. The company expects to make around 23 cents or 24 cents a share on an adjusted basis in the third quarter, below the 29-cent-a-share Thomson First Call target. Sales will be flat with the year-ago $208 million, substantially below the $237 million Wall Street estimate and the $230 million to $240 million target Nam Tai previously offered. Shares sank $3.24, or 21.6%, to $11.90 recently.

Atlantic Coast Federal ( ACFC) gained after the Waycross, Ga.-based bank said its board authorized a new stock repurchase program to replace a recently completed one. Under the new program, the company will purchase during the coming year up to 478,000 shares or about 10% of its currently outstanding publicly held shares of common stock. The new program will expire in August 2007 unless completed sooner or otherwise extended. In August, the company completed its second repurchase program. Under the second program, Atlantic Coast Federal repurchased 579,520 shares of its common stock for total consideration of about $9 million. Since 2005, the Company has repurchased about 865,000 shares. Shares gained 41 cents, or 2.3%, to $17.97 recently.

Excel Maritime Carriers ( EXM) gained after the Hamilton, Bermuda-based shipping company chartered the Panamax dry bulk carrier M/V Forteza for about 12 to 14 months at $28,000 a day to a first class European charterer. The vessel was delivered into charter on Aug. 30. As of the market's close on Thursday, 13 of the company's 17 vessels, or 76% of its fleet, are deployed on short- and long-term period charters with the remaining 4 vessels, or 24% of the fleet, trading in the spot market. Shares gained 38 cents, or 3.3%, to $11.94 recently.

Mannatech ( MTEX) gained after the Coppell, Texas-based nutritional supplementmaker said board of directors approved a second program permitting the company to purchase up to $20 million of its outstanding common shares in the open market. Shares gained 32 cents, or 2.21%, to $14.77 recently.