Even if we cede that Groupon would have had a better IRR for investors had they sold for $6bn; A move does not have to be correct with final knowledge to be correct with present knowledge.
My point is more that I don't think any information can be gleaned about whether rejecting this offer was a good idea from the fact of the rejection itself. You can look at this and say "Boy, they must know what they're doing to turn down that kinda scratch!" or you can look at it and say "They are crazy idiots."
The information that can be gleaned is that they internally value the company at a higher price.
My argument then, is that given that think about their company 24/7 and that they have access to data that I do not that they probably have a reasonable basis for believing that their company is worth more than the offer.
I further bolster my belief that their conclusions are reasonable with the fact that they have to justify their valuation to a board, many members of which represent IRR centric VC firms.
From the fact that a VC backed company rejects any offer you can glean quite a lot of information. Its a fairly simple exercise of "what had to happen?" and "what would you have to believe?".
