Like many business news outlets, TheStreet.com reports on yesterday's late announcement about Amazon.com's arrival on the S&P 500 index, which generated enough after-hours trading to spark a price increase of just over 6 percent. Don't read too much into it, though; "stocks joining major indices will often see a rise following such announcements," the Streeters reveal, "as index-based funds look to swap into shares of the latest inductee."

Still, that bump may have earned George Soros' investment fund more than $750,000 overnight. Soros Fund Management disclosed its Amazon holdings in a new filing, which also revealed substantial investments in Intel and eBay.