RSU vs stock options: which cuff binds harder?

Priya printed both offers and laid them on her kitchen counter on a Tuesday. Two senior-engineer roles, both quoting $400,000 in equity over four years. One from a public company she'd recognize on a stock ticker. One from a Series C startup with a customer list she already respected.

She read the equity section on the second offer and the comparison stopped being symmetric.

The first letter said RSUs (restricted stock units). Vest quarterly after a one-year cliff. Public stock, liquid market, the value you see on the offer is the value that lands in your brokerage. The second letter said options. Two hundred thousand of them, strike price $2, current 409A valuation $2, four-year vest with the same one-year cliff. Same headline dollar number on the offer summary. A different financial instrument underneath.

This is the rsu vs stock options decision every mid-career engineer ends up running at least once. The answer is not universal. The answer depends on which kind of binding you can tolerate. (The broader mechanics of multi-year vesting as a retention trap are covered in our main piece on golden handcuffs.)

The cuff is built differently

RSUs bind through forfeiture. The grant is a promise of stock. The stock arrives when the calendar says it does. If you leave before the vest date the unvested portion goes back to the company and you owe nothing. The cuff is what you lose by walking away.

Options bind through exercise cost. The grant is the right to buy stock at a fixed strike price. To turn that right into ownership you have to write a check, shares times strike, out of your own bank account. The cuff is what you have to spend to keep what you have already earned.

That difference is why the question "are rsu and stock options the same" gets answered no by anyone who has held both. They both retain employees. They retain them through opposite mechanisms.

Run Priya's numbers

Twelve months in, Priya has cleared the cliff at either company.

The RSU offer at the public co. Twenty-five percent of the $400,000 grant vests in the first year, so $100,000 of stock lands in her account. The IRS treats restricted stock units vs stock options very differently at this moment. The RSU vest is ordinary income, withheld at the federal supplemental rate of 22 percent on the first million, plus state, plus FICA. Call her all-in effective rate 35 percent. She nets about $65,000 in liquid shares she can sell that afternoon. IRS Publication 525 covers the income treatment.

The option offer at the private co. Twenty-five percent of 200,000 options vest, so 50,000 shares are now exercisable at the $2 strike. To buy them she would need to wire $100,000. If the 409A is still $2 there is no AMT spread and no tax yet. If a Series D bumped the 409A to $5 between her start date and her exercise, the spread on incentive stock options becomes an alternative minimum tax preference item: $3 times 50,000, or $150,000 of phantom income that can trigger a five-figure AMT bill in a year she received zero cash. IRS Topic 427 is the canonical reference.

That is the rsu vs stock options tax difference in one paragraph. The RSU is taxed when it vests, in cash she can sell. The option is taxed when she exercises, with money she has to find, against a value she cannot yet realize.

The 90-day window that decides everything

Most of the rsu vs stock options private company conversation collapses into a single clause buried on page seven of the option agreement: the post-termination exercise window.

The default for incentive stock options is 90 days. Leave the company on a Friday, and on the Monday three months later, any vested options you have not exercised are gone. To preserve them she would need to wire the $100,000 strike cost within 90 days of her last day, plus shoulder the AMT bill if the 409A has moved.

Some newer private companies have extended this window to seven or ten years. The IRS reclassifies the options from ISO to nonqualified after 90 days, which means ordinary-income tax on the spread at exercise instead of AMT preference treatment. The window stays open, but the tax treatment changes. The agreement language is what governs.

RSUs have no equivalent clause. They vest until you leave, and the unvested balance simply forfeits. Nothing to fund. Nothing to time.

Priya asked about two adjacent instruments while she was at it. The rsu vs espp question is a different category. An Employee Stock Purchase Plan lets her buy company stock at a discount through payroll deduction, usually 15 percent below market, with a six-month look-back period. It functions as a savings vehicle rather than a retention mechanism, and neither offer includes one. The 83(b) election applies to restricted stock and to early-exercised options at startups. It lets a recipient pay ordinary-income tax on the current low value within 30 days of the grant, which can save real money if the company appreciates. The election does not apply to standard RSUs.

Which cuff is tighter

The honest answer to rsu vs stock options which is better is the one most candidate guides skip past. The RSU at the public company is the tighter cuff in cash terms. Every quarter the vesting schedule prints a known dollar amount against a liquid share price. Walking away at month 18 costs her exactly $300,000 in stock she can see on a screen. The trap is legible.

The option at the private company is the tighter cuff in optionality terms. Exercising commits real cash today, against an exit she cannot price and a 90-day clock she cannot extend. The decision is harder because the numbers are softer. The trap is illegible.

Both retain you; they just pull on different things. The RSU holds your money — a visible number you forfeit by leaving. The option holds your flexibility: cash you have to spend, on a 90-day clock, to keep what you already earned. Priya took the startup option, with her eyes open about the exercise bill she would owe if she ever wanted out.