5btc/share is a ridiculous estimate (sorry, but it is).

Assuming the global network hashrate is 6PH by Jan 1 and Labcoin is hashing @ 500TH/s, that is 8.33% of the global network.

A conservitive estimate of global bitcoins mined in a 2 week period is 56,000 (4,000 x 14).

8.33% of 56,000 is 4666.648 bitcoins divided by 10,000,000 shares is .0004666 / share.

~30% is removed for costs/reinvestment etc.

Final result: .0003266/share for the 2 week period. (roughly .0085 annually) for a share price of .0339 @ 25% annual return.

Of course this is entirely unrealistic as nobody would at this point trust labcoin enough to be happy with a 25% annual return.