Blue Chips Open Lower; Techs Up  NEW YORK (Reuters) - Blue chips opened lower on Thursday,  weighed down by news that insurer American International Group  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=AIG.N target=/stocks/quickinfo/fullquote"&gt;AIG.N&lt;/A&gt; was being investigated by a federal grand jury, while  techs rose on eBay &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=EBAY.O target=/stocks/quickinfo/fullquote"&gt;EBAY.O&lt;/A&gt; earnings.