Borders Posts 3rd-Quarter Loss Vs Yr. Ago  SAN FRANCISCO (Reuters) - No 2. U.S. book retailer Borders  Group Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=BGP.N target=/stocks/quickinfo/fullquote"&gt;BGP.N&lt;/A&gt; on Tuesday posted a quarterly loss versus a  year-ago profit, hurt by sluggish store traffic and a slowdown  in sales of bestsellers.