MNB Chart, page-258

To make the explanation clearer to illustrate, take the following example.
Say the shares are at 16c and the options are 7c. They were my switch prices today (7.2c ave buy price to be exact). To convert the options you need to pay another 15c for a total of 22c. 22c was 6c above the sp so the options traded with a 6c time premium. Generally the greater the time to expiry, the greater the time premium.
Now, let's say in a year, the shares reach 64c. That is my expectation and why I'm prepared to pay a premium on the options. The market has been at a larger premium for the last few months.
At 64c, the shares will have quadrupled. Let's assume that the options will lose all of their premium as there is less time to expiry. The options would then trade at 64-15 or 49c.
The options have gone up 7 fold providing a much larger profit than the 4 fold increase for the shares, despite the up front premium paid and despite the assumed complete loss of the premium. If the shares go up more quickly, less premium will be lost and the option out performance would be greater.