Restricted Stock Awards (RSA) vs RSUs: What the Tax Difference Actually Means

RSAs and RSUs are both "equity compensation," but they are taxed under entirely different rules — and the decisions you make when an RSA is granted (specifically, whether to file an 83(b) election within 30 days) can be worth hundreds of thousands or millions of dollars at exit. Most startup employees don't understand this until it's too late.

The core difference in one sentence

An RSA is actual shares issued to you now, subject to a vesting/forfeiture schedule. An RSU is a promise to issue shares later, when they vest. That difference in ownership timing is what drives every tax rule below.

What is a Restricted Stock Award (RSA)?

An RSA is a grant of actual company shares. You own the stock on the grant date — it's on the cap table under your name. But the company retains a right to repurchase the shares (at cost or at a formula price) if you leave before they vest. The "restriction" is that forfeiture right, not a restriction on ownership itself.

RSAs appear most often at early-stage startups:

• Founders receiving co-founder shares (often millions of shares at $0.0001/share, with 4-year vesting + 1-year cliff)
• Employees #1–50 at seed and Series A companies, where 409A valuation is still very low
• Advisors and contractors receiving small restricted stock grants at nominal value

Because RSAs involve immediate share issuance, you typically have voting rights and can sometimes receive dividends from day one — even on unvested shares, if the company's stock plan allows it. The practical implication: an RSA with an 83(b) election can start the QSBS clock immediately, and gives you capital-gain (rather than ordinary-income) treatment on all appreciation from the grant date.

What is an RSU?

An RSU is a promise to deliver shares when vesting conditions are met. There are no actual shares until the vest date — no cap table entry, no voting rights, no 83(b) election option. On the vest date, the shares are delivered and the IRS treats the fair market value as ordinary income under IRC § 83(a) — automatically, with no election available.

RSUs dominate at large public companies (FAANG, pre-IPO unicorns with mature equity plans) for a simple reason: the shares have real value from day one, so the company doesn't want employees to have legal ownership until vesting. RSUs also avoid the "forgot to file 83(b)" liability that causes problems with RSAs.

Side-by-side comparison

The 83(b) election for RSAs: the decision that matters

When you receive an RSA, you have a one-time, irrevocable choice within 30 days of the grant date: file an 83(b) election with the IRS or don't.¹ This choice determines which of two very different tax tracks you end up on.

Track A: RSA with 83(b) election filed

You elect to include the current FMV of the shares in your ordinary income immediately — even though the shares aren't vested. At an early startup, the 409A valuation is typically very low, so the income inclusion is tiny. You pay tax on $0.01/share on 500,000 shares: $5,000 of ordinary income. That's a small tax check you write voluntarily to "buy" a much better tax track.

What you get in exchange:

• Your tax basis in the shares is the FMV at grant date ($0.01/share). Any future appreciation — including all the company's growth from Series A through IPO — is a capital gain measured from that basis.
• If you hold the shares for at least 12 months from the grant date, all post-grant appreciation is taxed at long-term capital gains rates (15–20% federal plus NIIT, versus 37%+ ordinary income rates).
• You start the QSBS § 1202 holding period clock immediately — potentially qualifying for up to $15M of federal tax exclusion on gains after 5 years, if the company qualifies.

Track B: RSA without 83(b) election — or RSU (same track)

Without an 83(b) election, an RSA is taxed exactly like an RSU: each time shares vest (become non-forfeitable), the IRS treats the FMV at that moment as ordinary income. If you received 500,000 RSA shares at a nominal grant-date FMV but they vest over 4 years while the company grows from $10M to $500M valuation, most of your income is taxed at ordinary rates on the way up — the same outcome you'd have with RSUs.

Filing the 83(b) election: mechanics

The 30-day deadline is hard

You must file the 83(b) election within 30 calendar days of the grant date. There are no extensions. The IRS has refused to grant relief for late elections even with demonstrated hardship. If you miss the window, you're on Track B permanently for that grant.¹

Electronic filing via Form 15620

As of 2024, the IRS introduced Form 15620, an official electronic 83(b) election form filed directly through the IRS online portal. Before Form 15620, elections required a letter with multiple mailed copies and certified mail confirmation. Form 15620 simplifies the process significantly — but the 30-day deadline still applies. See the full 83(b) election guide for step-by-step filing instructions and a copy requirement checklist.

What to include in the election

The election must describe the property (shares received, company name, grant date), the FMV at the time of transfer, the amount paid for the shares, and the restriction that creates the risk of forfeiture. Your company's legal counsel or equity platform (Carta, Pulley, etc.) often provides a pre-filled template — but verify it before submitting.

Three scenarios: the tax math side by side

Assume: seed-stage employee receives 400,000 RSA shares on January 1, 2026. Grant-date FMV: $0.05/share (409A). 4-year vesting, 1-year cliff. Company IPOs in 2029 at $25/share. Shares fully vested by 2030.

Illustrative only. State taxes, holding period variations, and AMT can all shift this math. California residents note: QSBS exclusion is not recognized by California, so state tax (up to 13.3%) still applies on the full gain.

QSBS interaction: the biggest multiplier

If your company qualifies as a Qualified Small Business under IRC § 1202 — C-corp, gross assets under $75M at issuance, active business in a qualified industry — the federal tax on up to $15M of your gain can be zero after 5 years.²

The 83(b) election is what makes this possible for early employees:

• With 83(b): your holding period starts on the grant date. A January 2026 grant reaches 5 years in January 2031 — well before most IPO lockups expire.
• Without 83(b) or with RSUs: your QSBS clock starts at each vest date. Shares vested at the cliff in January 2027 don't hit 5 years until January 2032. Shares vested in 2028 don't qualify until 2033. The lockup may expire long before you've held long enough.

For a $10M position, the QSBS exclusion can save $2.38M in federal tax — just on the Roth-like treatment of gain. Combined with the ordinary-income-to-LTCG shift from the 83(b) election, the total tax advantage of getting this right at grant can easily exceed the number on your offer letter. See the full QSBS guide for company-level qualification steps and the OBBBA $15M rule.

The forfeiture risk with 83(b)

One genuine downside of the 83(b) election: if you leave the company before your shares vest, you forfeit them — and you cannot recover the taxes you paid on the grant-date FMV. The company repurchases the unvested shares at the original purchase price (often nominal), and the loss is typically a capital loss (not an ordinary-income offset).

For early startup employees where the grant-date FMV is near zero, this risk is minimal. If you paid tax on $5,000 of income and then forfeit the shares, you lose $5,000 in basis and the opportunity cost is small. The math shifts if the company's 409A has risen significantly by the time you're considering early exercise — at that point, the upfront income inclusion is larger and the forfeiture downside is real.

RSAs vs RSUs: which will you encounter?

In practice, the choice is usually made for you by your employer's equity plan and stage:

• RSAs are common at: pre-seed and seed-stage startups, founding teams, early advisory grants, companies using Carta or Pulley where the 409A is $0.01–$0.50/share.
• RSUs are common at: public companies (Apple, Google, Meta), late-stage unicorns with 409A valuations in the $10–100/share range, companies whose prior employees experienced the pain of RSA forfeiture and switched equity plans.

If you're evaluating a job offer at a startup with meaningful equity, ask specifically: are these RSAs or RSUs? If RSAs, ask: what's the current 409A valuation, and what's the process for filing an 83(b) election? The equity offer calculator is useful for understanding after-tax proceeds — see the startup equity offer calculator — but understanding the instrument type changes the tax plan entirely.

When to involve an advisor

The 30-day 83(b) window is the most time-sensitive decision in startup equity. Advisors who specialize in equity compensation can:

• Confirm whether your RSA grant qualifies for an 83(b) election and whether QSBS applies
• Model the tax comparison between filing and not filing given your specific FMV, vesting schedule, and other income
• Confirm the company's 409A valuation and QSBS eligibility before you commit
• Handle the Form 15620 filing or attorney review of the election letter
• Advise on the state-tax implications of QSBS (especially California nonconformity)

Sources

1. IRS Rev. Proc. 2024-37 — Guidance on § 83(b) electronic election via Form 15620; 30-day filing deadline under IRC § 83(b) and Treas. Reg. § 1.83-2(b).
2. IRC § 1202 — Partial exclusion for gain from qualified small business stock; post-OBBBA $15M exclusion cap and $75M gross assets threshold.
3. IRC § 83 — Property transferred in connection with performance of services; general rule for RSAs and RSUs.
4. IRS Rev. Proc. 2025-32 — 2026 LTCG rate thresholds: 0% up to $49,450/$98,900 (single/MFJ); 15% up to $545,500/$613,700; 20% above; NIIT 3.8% above $200K/$250K under IRC § 1411.

Tax values verified for 2026. QSBS rules as amended by the One Big Beautiful Bill Act (signed July 4, 2025). RSA and 83(b) election rules are not subject to annual inflation adjustments but consult a tax professional for your specific facts.