So what it means is the options that have been issued (the same I believe as all the others in recent history) are vested over a 4 year period. That means that 25% of the awarded options can be exercised each year over the next four years so long as the recipient continues to be employed by the company.  And if they continue to stay with POET the options remain available to them over the next ten years. Sounds like a great deal to me but options that vest over 4 years is not something you normally see (in my experience). I suppose it takes a bit of the sting out of the numbers?