why minemakers is the best phosphate play, page-20

Apologies eed to correct that, as I wasn't taking into account the price of the option.

Say you bought the option at 24c, and an equivalent head at 54c. You intend to sell the head to exercise an option.

At 50c, you incur a loss of 4c on the sale.
You then fund the option with 30c and have 20c remaining, however this doesn't cover the cost of the option 24c, so you have a 4c shortfall plus your loss of 8c the heads.

In this situation, it's not worth converting the options at 50c!

You'd have to trade heads at 54c to make it a value proposition. This actually explains the current level better.