Don't buy the stock outright. Use the single stock futures, they are trading at a discount due the short borrow rate being so high. Call it a discount coupon on Groupon
the last seems to be wrong. I don't know, I got a chart from IB showing less of a discount. The most important thing is the Ask from the SSF market maker though
LOL the SSF for Jun 2012 has a $2 bid ask spread. You can buy GRPN at a $1 discount though by hitting the ridiculous ask from the MMrs $2, its fucking hilarious that the market marker is making the market so wide