DOW JONES NEWSWIRES Borders Group Inc.'s (BGP) fiscal third-quarter loss widened sharply as sales continued to slide and margins declined. Chief Executive Mike Edwards said he was "disappointed" with the company's results, which "reflect the business challenges facing Borders and the industry at large." Shares dropped 6.6% to $1.28 after hours, erasing some of this week's 27% gain following investor Bill Ackman saying he would be willing to finance a $960 million takeover bid for larger rival Barnes & Noble Inc. (BKS). Borders, the No. 2 U.S. bookseller by sales, has struggled heavily amid a sharp decline in sales and customer traffic, while its margins have continued to fall. The bookselling industry as a whole has struggled to grapple with the rise in popularity of digital books. But Barnes & Noble said last week that its quarterly loss narrowed as its results were boosted by its recently acquired college-bookselling business. For the quarter ended Oct. 30, Borders reported a loss of $74.4 million, or $1.03 a share, compared with a year-earlier loss of $37.7 million, or 63 cents a share. Revenue dropped 18% to $475.6 million as same-store sales dropped 13%. Gross margin fell to 15.4% from 18.5%. -By Nathan Becker, Dow Jones Newswires; 212-416-2855; nathan.becker@dowjones.com;