The price an investor is willing to pay for an option depends on a number of factors including interest rates and the relationship between the market price and the exercise price.
For investor A to buy the right to "call" the shares of Goldman Sachs at a certain price one year from now, there has to be an investor B willing to take the other side of the trade and sell those shares if A decides to transact.
And the reason for that is very simple: Public companies are always willing to pay more for a stock than a private investor would, because of something called the liquidity premium.
Of the four, Amgen was willing to help Tularik straighten out its capital structure by buying out a major investor who had lost interest, notes the Deloitte report.
America has a huge retail and institutional investor base for such companies, with armies of clever analysts and investors willing to throw money at promising ideas and pull it out of others.