Did big banks turn blind eye to Groupon's odd accounting?

The company was supposed to be valued at $30 billion when it goes public, but now, its valuation looks to be more in the $10-billion range--if it's lucky.<img src="http://feeds.feedburner.com/~r/cnet/tcoc/~4/OjN11CDhc6M" height="1" width="1"/> [More]