If there is no market, either because it is pre-IPO or unvested then the value is unrealized, and therefore not a form of compensation, so no. You don't own eq

If there is no market, either because it is pre-IPO or unvested then the value is unrealized, and therefore not a form of compensation, so no. You don't own equity that haven't vested. They are just a contract between you and the employer to transfer them to you upon vest, which either party can probably walk back on if they choose to.