RSA vs. RSU Explained: Why It Changes When You Actually Own Your Equity

An RSA (restricted stock award) gives you actual shares on the day you're granted them, subject to the company's right to buy them back if you leave before they vest. An RSU (restricted stock unit) is a promise to deliver shares later, at vesting; you own nothing until then. That difference changes when you're taxed, whether you can file an 83(b) election, and what you keep if you leave early.

Offer letters often just say "equity" or list a share count without naming which type you're getting, and that single word matters more than it looks.

What Is an RSA vs. an RSU?

An RSA makes you a shareholder on the grant date itself; an RSU only makes you one once each tranche vests. Everything else, including taxes and what happens if you leave, flows from that one distinction.

RSAs: You Own the Stock at Grant

With an RSA, the company issues you real shares immediately, usually for a nominal purchase price. You hold those shares from day one, but they're "restricted": if you leave before a tranche vests, the company can typically buy back the unvested portion at what you originally paid, per Carta's RSA vs. RSU comparison. Vested shares stay yours outright.

RSUs: A Promise to Deliver Stock Later

An RSU is a contractual right to receive shares in the future, with nothing issued at grant. You don't own stock, can't vote it, and owe no tax until each tranche actually vests and settles into real shares. There's nothing to buy back if you leave early, because you were never issued anything to lose; the unvested units are simply canceled.

Why Companies Grant RSAs at the Earliest Stage and RSUs Later

Companies default to RSAs when common stock is worth pennies, and switch to RSUs once it's worth real money, because the tax math stops favoring employees otherwise.

Low Fair Market Value Makes RSAs Cheap Early On

At a brand-new startup, the fair market value (FMV) of common stock is often a fraction of a cent per share, so buying at that price costs almost nothing, and the taxable gap between purchase price and FMV is close to zero. That's exactly the setup an 83(b) election is built for, covered below.

RSUs Take Over Once Strike Prices and FMV Climb

As a company's valuation grows, issuing shares to every new hire at a much higher FMV creates a real tax bill on day one. RSUs sidestep that by deferring the share issuance, and the tax hit, until vesting; Carta notes that mature and public companies favor RSUs precisely because FMV is already substantial. As a rough pattern, pre-seed and seed-stage companies grant RSAs while companies past a meaningful round, or public, shift to RSUs, though it's a trajectory, not a rule. Our RSU vs. stock options comparison covers the related units-versus-options question.

Taxation: When You Owe and How Much

RSAs are taxed on the spread between what you paid and FMV, assessed at grant (with an 83(b) election) or at each vest (without one); RSUs are taxed as ordinary income on the full value of each tranche at vest, with no election available.

RSA Taxation Without an 83(b) Election

Without an election, you're taxed as each tranche vests, on the difference between FMV at that moment and what you paid. Because FMV generally rises over time, waiting usually means a bigger tax bill than being taxed once at grant, when the stock was cheapest.

RSU Taxation at Each Vesting Date

RSUs don't offer a choice here: you owe ordinary income tax on the full FMV of the shares the moment they vest and settle, full stop. There's no grant-date election, because you don't own anything at grant to elect on. Any gain after that point, on either instrument, is a separate capital gains question that varies by state and filing status, so treat specifics here as background, not a substitute for a tax professional.

The 83(b) Election and Why It Only Matters for RSAs

An 83(b) election lets you choose to be taxed on restricted stock at grant instead of at vesting, and it only applies to RSAs (and early-exercised stock options), because RSUs don't transfer any property to you until vesting.

The 30-Day Deadline

The election has to be filed with the IRS within 30 days of the grant (or early exercise), with no extensions. Pulley's guide to RSAs walks through how filing within that window, while FMV is still near the purchase price, can reduce recognized income to close to zero. We cover the full mechanics in our 83(b) election explainer.

Why RSUs Don't Qualify for an 83(b) Election

An 83(b) election applies to property you've already received. Since an RSU holder receives nothing until vesting, there's no "receipt" to elect on early, which is the whole reason RSUs work as a tax-deferral tool for mature companies.

The Risk If the Company Fails

Filing means paying tax now on stock that could turn out worthless later if the company fails, and that tax isn't refundable. It's a bet on the company's survival, made with real cash, often before you have much information on whether that bet will pay off.

What Happens to Your Shares When You Leave the Company

If you leave before full vesting, RSA holders keep vested shares but risk losing unvested ones to the company's repurchase right; RSU holders simply lose unvested tranches outright, since those units are canceled, not bought back.

RSA Unvested Shares: Company Repurchase Right

Because you already legally own RSA shares from grant, the company can't just take unvested ones back automatically. The grant agreement typically gives it an option to repurchase unvested shares, usually at the price you paid, when you leave. It's a right the company can choose to exercise, not an automatic clawback, though most do in practice.

RSU Unvested Units: Automatic Forfeiture

RSUs skip the repurchase question entirely: since you never owned the underlying shares, there's nothing to buy back. Unvested units are simply forfeited the moment employment ends, the mechanic covered in our post on what happens to unvested RSUs after a layoff, which applies whether you're laid off or resign.

Vested Shares Are Yours Either Way

Whatever has already vested, as RSA shares at grant or settled RSU shares at vest, is yours regardless of why or how you leave. The fight is always over the unvested portion, which is why vesting schedule details, like the ones covered in our vesting cliff explainer, matter so much.

How to Tell Which One You Have From Your Offer Letter

The clearest tell is the vocabulary: documents that say "restricted stock award" or "RSA" and mention a purchase price are RSAs; ones that say "restricted stock unit" or "RSU" and describe a settlement or delivery date are RSUs.

Language to Look For

Look for whether the document mentions "purchasing" shares at grant, even a trivial amount, or only describes "units" that will "settle" later. A reference to an 83(b) election anywhere in your paperwork is also a strong signal you've been issued an RSA, since that election doesn't exist for RSUs.

Questions to Ask If It's Not Clear

If your offer letter just lists a share count under "equity," ask directly: "Is this a restricted stock award or a restricted stock unit, and is there a purchase price I need to pay?" That also tells you whether an 83(b) deadline is already running. Getting it wrong by even a few weeks can cost you that election window on an RSA grant. Offer XRay is built to flag exactly this kind of ambiguous equity language when you upload an offer letter for review.

Frequently Asked Questions

Is an RSA the same as "restricted stock"?

Yes, "restricted stock" and "RSA" generally mean the same thing: shares issued at grant, subject to a vesting-linked repurchase right. "Restricted stock unit" (RSU) is a different instrument despite the similar name.

Do RSU holders get voting rights before vesting?

No. Since RSUs don't transfer shares until they vest, there's nothing to vote with beforehand. RSA holders typically do get voting rights from the grant date, including on unvested shares, since they already own the stock.

Which is better, an RSA or an RSU?

Neither is inherently better; which one you're offered is mostly a function of your company's stage and share price, not a choice either side makes freely. An RSA can be more tax-advantageous if FMV is very low and you file an 83(b) election promptly, while an RSU avoids any upfront cash outlay in exchange for giving up that early tax-timing choice.

Key Takeaways

• An RSA issues real shares at grant, subject to a company repurchase right on anything unvested; an RSU issues nothing until vesting.
• Only RSAs (and early-exercised options) are eligible for an 83(b) election, and the filing deadline is a strict 30 days from grant.
• If you leave early, RSA holders keep vested shares and risk losing unvested ones to repurchase; RSU holders simply forfeit unvested units outright.
• Your offer letter's exact wording, "award" with a purchase price versus "unit" with a settlement date, tells you which instrument you actually have.
• Tools like Offer XRay flag ambiguous equity language automatically, and pricing starts at $4.99 for two analysis credits.

The word "equity" can hide two genuinely different deals, and the gap shows up exactly when it matters most: at tax time and your last day. Confirm which instrument you're being offered and whether an 83(b) clock is already running before you sign. If you'd rather have that language checked automatically, try Offer XRay on your own offer letter.