For tax purposes, you don't want Founder's shares to vest. It's important they are straight shares, for example, to be treated as QSBS and start the 5-year time

For tax purposes, you don't want Founder's shares to vest. It's important they are straight shares, for example, to be treated as QSBS and start the 5-year timer on Day 1 so that the first $10 million in equity is tax free if you make a sale. You can instead add a buy-back provision, which expires in tranches over time (basically this is re-inventing vesting but in reverse). One real problem I've actually had with such a buyback provision is when the early employee leaves, according to the agreement you are entitled to buy-back 80% of their shares, but then they refuse to cash the buyback check or sign a document agreeing that the shares have indeed been bought back. Now you're back again in this legal limbo. So next time I do a buy-back provision on Founder's shares, I'm going to pre-fund the whole buyback, and then if they leave, the departing employee will owe the company a partial refund of the buy-back. Since it's Founder's shares at par value, if they refuse to pay it then it's by far the lesser of 2 evils. E.g. Co-Founder pays $100 par value for shares. Company pays Founder $100 to pre-fund the buyback. Co-Founder leaves after 6 months and Company buys back 8,750 of 10,000 shares. Co-Founder technically owes the company $12.50.