Restricted Stock Units: Understanding Vesting, Taxation, and Strategy

What are RSUs?

Restricted Stock Units, or RSUs, are a form of equity compensation that represents a promise to deliver shares of company stock after you meet certain conditions — typically continued employment over a vesting schedule. Unlike Incentive Stock Options (ISOs), which require you to exercise and pay a strike price, RSUs are automatically converted to shares when they vest. You don’t have to do anything. The downside: RSUs are taxed as ordinary income the moment they vest, regardless of whether you sell the shares or hold them.

The Vesting Schedule

RSUs follow a vesting schedule, often spanning 3-5 years, sometimes with a cliff. Following the cliff (if any), the remaining shares typically vest monthly, quarterly, or annually over the remainder of the vesting term. The vesting schedule is critical because it directly determines when you owe taxes.

The Tax Hit at Vesting

Here’s the key point: you owe income tax on the day your RSUs vest, based on the fair market value (FMV) of the stock on that vesting date. If you received 10,000 RSUs at a $80 purchase price, and they vest when the stock is trading at $100, you owe ordinary income tax on the $20 spread — $100,000 of ordinary income, taxed at your marginal rate, potentially as high as 37%. This can create a major cash flow problem. You’ve received stock you didn’t buy, yet you owe taxes immediately. Many employees find they need to sell some shares to cover the tax bill. This is why understanding RSU taxation matters: it affects your cash flow in real-time.

Withholding and Tax Reporting

Most companies automatically withhold shares to cover your estimated tax liability when RSUs vest. If you owe taxes on $100,000 of income and your marginal rate is high, your company might withhold a sizable amount (in shares) to cover federal, state, and payroll taxes. You end up with fewer shares than you expected.

Important caveat: RSU withholding rates often differ from your actual marginal tax rate. Federal supplemental wage withholding is typically a flat 22% (or 37% above $1 million), which can leave a high earner significantly under-withheld — meaning additional taxes owed at filing time, and possibly underpayment penalties. The withholding is an estimate, not a final settlement.

Here’s where it gets important for tax reporting: that withholding appears on your W-2 as ordinary income. It flows through your annual tax return as part of your W-2 income — just like your base salary, bonus, overtime, and any other payroll income. Because it’s treated as compensation, it’s also subject to the Additional Medicare Tax of 0.9% on Form 8959 if your total Medicare wages exceed the threshold for your filing status.

Later, when you sell those shares, any gain or loss between the vesting price and your sale price is reported separately on your brokerage statement as a capital gain or loss. So if your RSUs vest at $100 and you sell at $130, that $30 gain per share is a capital gain, not ordinary income. Capital gains are generally not subject to the Additional Medicare Tax, though they may be subject to the 3.8% Net Investment Income Tax (NIIT).

Holding for Long-Term Gains

After your RSUs vest and you own the shares outright, any appreciation is subject to capital gains taxation. If you hold the shares for more than one year after vesting, that appreciation may qualify for long-term capital gains rates — usually 15% or 20% (depending on income), but surely less than your marginal tax bracket rate. Again, the NIIT of 3.8% may also apply if your modified adjusted gross income exceeds certain thresholds.

This creates a question worth considering: whether to hold the shares after vesting or to sell immediately. Holding may make sense if you have conviction in the company’s direction and can tolerate the volatility. Selling immediately may make sense if you prioritize diversification or have other financial goals. Both approaches have tradeoffs worth considering based on your personal situation.

The Takeaway

RSUs are straightforward but tax-inefficient. Plan for the tax bill at vesting, understand your company’s withholding mechanics, and know where to expect your gains reported — W-2 for the vesting bargain, and your brokerage statement for any later appreciation. Unlike some equity structures, there’s no way to defer or optimize the income tax hit at vesting — it’s built into the structure. The primary decision you control is whether to hold or sell after you own the shares.