Brad Feld, VC extraordinaire, has this excellent post about the compensation that early stage advisors should get. What is more interesting is that Brad actually talks numbers!!!
For example, 1% vested over four years is in the top range of the compensation bracket. What Brad usually prefers is 0.25% <=x <=1%.
However, one of the more interesting aspects of this is trigger acceleration of vesting.
'Tis very simple actually; I put my blood 'n sweat in the Company; Company gets acquired; I get screwed out of my options.
The alternative is to have a clause that says – In the event of a M&A only (single trigger event), or else a M& followed by me getting fired (double trigger event), I will get automatic acceleration of n on my vesting.
The other interesting aspects coming out of his incomparable term sheet series , is that it could be more advantageous to have a vesting period of one year and re-visit the relatioship after that as well as no-cash-compensation.
Cool. Now about that company….

