It's pretty funny to see this compared to the S&P 500. Liquidity premiums alone could easily account for the difference in returns. I'd take 20% cash gains over 40% utterly illiquid gains any day. Much more interesting statistics would be expected % value realization. Then multiply the 40% gains by that number. For example, if your gains are 40% multiplied by 20% of the startups ever making an exit, your actual returns are 8%.