For those who dont want to sell...

Even if bob is able to get the hash up to 10gh/s and keep it there (unlikely) and the difficulty goes up by 25% (conservative) we will never see $290 per share

http://btcinvest.net/en/bitcoin-mining-profit-calculator.php?diff=908350862.43702&dcosts=0&diff_mincrease=25&blpbtc=25&dhsmhs=10000&diff_mincreasedecrease=0.1&btcusd=832.64&dpowcon=0&btcusd_mincrease=0&pcost=0&calcweeks=20&dleadtime=0&action=calc

http://bitcoinwisdom.com/bitcoin/calculator

selling is the best option!