Here's the thing: it's incredibly difficult to say that. Most investors build themselves a nice legal framework to make sure that they are very likely to get some amount of money back.
Regardless of the company, investors most likely made sure that they get some sort of preference, whether it's in anti-dilution preference, liquidation preference, etc. If the company tanks, or even just doesn't live up to expectations, investors will most likely get some sort of compensation (maybe less than they invested, but it's unlikely that they'll lose 100% of their investment).
Then there's the question of even if things go reasonably well, is it worth it. First, you have to address the time value of money, which basically is a question of what else you could have done with the money in the meantime.
If you get $100k after 5 years at a company, that sounds like a good chunk of money, but is essentially $20k/year before taxes, and the tax implications that will likely be worse if you get $100k in a windfall vs. compensation.
Then consider that even if the company does "well", there's a decent chance that employees won't see nearly as much money as they expect. One question I've wanted to ask for awhile is what happened to employees at Loopt, Sam Altman's company. According to CrunchBase, they raised $39m+, and sold for $43.5m according to Wikipedia. If everything converted to common stock, employees with 0.5% would get $217k (before taxes).
However, depending on investors, there's a good chance that employees got nothing. Outside of dilution, there are a bunch of other things that can really ruin your "investment": the preferences mentioned above, cases where their initial investment is returned before the profits are split, and multipliers (investors are guaranteed a multiple of their investment in return).
So there's no real easy way to say what percent of companies pay back their investors. Colossal failures can still make money for investors (via the multipliers mentioned above), even though employees who exercised their options are screwed (they bought their shares AND paid taxes on them).
Regardless of the company, investors most likely made sure that they get some sort of preference, whether it's in anti-dilution preference, liquidation preference, etc. If the company tanks, or even just doesn't live up to expectations, investors will most likely get some sort of compensation (maybe less than they invested, but it's unlikely that they'll lose 100% of their investment).
Then there's the question of even if things go reasonably well, is it worth it. First, you have to address the time value of money, which basically is a question of what else you could have done with the money in the meantime.
If you get $100k after 5 years at a company, that sounds like a good chunk of money, but is essentially $20k/year before taxes, and the tax implications that will likely be worse if you get $100k in a windfall vs. compensation.
Then consider that even if the company does "well", there's a decent chance that employees won't see nearly as much money as they expect. One question I've wanted to ask for awhile is what happened to employees at Loopt, Sam Altman's company. According to CrunchBase, they raised $39m+, and sold for $43.5m according to Wikipedia. If everything converted to common stock, employees with 0.5% would get $217k (before taxes).
However, depending on investors, there's a good chance that employees got nothing. Outside of dilution, there are a bunch of other things that can really ruin your "investment": the preferences mentioned above, cases where their initial investment is returned before the profits are split, and multipliers (investors are guaranteed a multiple of their investment in return).
So there's no real easy way to say what percent of companies pay back their investors. Colossal failures can still make money for investors (via the multipliers mentioned above), even though employees who exercised their options are screwed (they bought their shares AND paid taxes on them).