Good luck shorting this illiquid closely held growth stock.
I agree that it is expensive (and regrettably have sold Sept 150 calls against my stock), but the field is littered knee deep with the corpses of those who have shorted SAM. Pray consider the fate of those who were part of the 30% short interest around Dec 12th last year (when SAM was about $113). Care to share their miserable fate?
The market, particularly for SAM, appears to be able to stay irrational longer than most shorts can stay solvent. Short away, and may the margin calls be with you!