I think you already know the answer because of the way you're asking the question. If you think you're underpaid on a salary basis and you don't have any large

I think you already know the answer because of the way you're asking the question. If you think you're underpaid on a salary basis and you don't have any large compensatory benefits like equity it just follows that you're underpaid. Whether you make the difference up in equity, cash or something else is up to you but generally you could consider equity or some cash performance/bonus option.