First, your stock has a much higher than 50% chance of being worth less, even at the best startups. This is why early stage investors invest in so many companies… a vast majority are worth zero, but the few that make it big pay for all those and more.

This is why you would never see an early stage investor invest in only one company. They need volume to be able to survive the high risk/high reward nature of startup investing.

Now, maybe you think you are a better judge of the probability of success for your startup than an investor, so the risk is lower. You would be wrong; if there was a way to reliably predict which startup would hit it big, then investors (who spend all their time trying to predict exactly that, and have a lot more data and history to use in their evaluation than you do as an employee) would have a much higher success rate.

So even if you have a very promising startup, your equity is a huge risk. Your company probably won’t hit it big, and if it does you have to hope you aren’t screwed out of your equity by the millions of tricks they use to screw employee shareholders; dilution, preferred shares, etc.

Even worse, you are taking double risk. Your startup is risking both your equity AND your salary. You want to diversify your risk, so you can use your investment when your salary fails and use your salary when your investment fails. In this case, those both will fail together if your company doesn’t make it.

Look, equity and stock options are great, but you REALLY have to discount its value as an employee because of the way the risk shakes out as an employee.