Wouldn't RSUs open employees to a different and more punitive tax regime (income tax) than options (which would fall under capital gains if you exercised early enough)?
RSUs are simpler and can be planned for. For example, a company could grant RSUs with a mandatory buy back vesting schedule (basically 83b election) upon hire and include the taxes as part of the comp package.
Examples:
Junior Engineer Sally joins Company A and is offered 0.25% of the company in RSUs. Company A recent raised at a 20M post money with a preferred share price of $1 and a FMV of $0.20. She owes tax on $10k of RSU gains. Company A either: 1) Buys back $4000 of stock in order to cover taxes 2) Provides a $4000 signing bonus to cover taxes.
Senior Engineer Bill joins Company B and is offered 0.05% in RSUS. Company B recently raised at a $500M valuation with a preferred share price of $10 and FMV of $3. He owes tax on $75k of RSU gains. Company B either 1) Buys back $30k of stock or 2) provides a $30k signing bonus.
But, you have to pay income tax on the value of the shares at the time when they vest, i.e. become non-restricted. You have zero control over that vesting schedule, and thus the tax bill, and you likely wouldn't have a liquid market for the shares before an IPO.
Any gain post-vest can indeed be long-term cap gains, if you hold the shares > 1 year.
