I have this bet with Paul Kedrosky:

• If Groupon’s market cap falls below $6 billion on any day on or before June 3, I win.
• If Groupon’s market cap stays above $6 billion until after June 3, Paul wins.

Market cap is measured as the market cap at the end of trading on any day, as reported by Google Finance. Intraday dips don’t count.

$6 billion is the price that Google reportedly offered for Groupon.

Stakes: loser buys dinner at restaurant of winner’s choice when we’re in the same city.

Update: A day late and $200 million short! Groupon closed above $6 billion on June 1, but below $6 billion on June 4. The markets weren’t open on June 3. (I didn’t check the calendar before proposing the bet.) On the plus side, I’m now in the win column on my bets with Semil Shah and Felix Salmon.