RSUs (Restricted Stock Units)
An RSU is a promise to deliver shares on a future date (or dates), contingent on your continued employment. When an RSU vests, you receive actual shares — or their cash equivalent if the company settles in cash.
**Tax:** RSU income is recognized at vesting, at ordinary income rates. The company typically withholds shares to cover taxes — so you receive fewer shares than the full grant, but you owe no additional taxes at vesting (assuming your marginal rate is covered by withholding). When you later sell the shares, any gain from the vest price is taxed at capital gains rates.
**Key feature:** RSUs have value as long as the stock is worth anything above zero. They do not require you to pay to exercise. This makes RSUs lower-risk than options.
Stock Options
An option gives you the right (but not obligation) to purchase shares at a fixed price — the "strike price" or "exercise price" — set at grant date. If the stock price rises above the strike, you can buy at the lower strike price and either hold or sell at market value.
**NSO (Non-Qualified Stock Options):** The spread between strike and market price at exercise is ordinary income. Most commonly issued to employees and advisors.
**ISO (Incentive Stock Options):** If held long enough (2 years from grant, 1 year from exercise), gains qualify for long-term capital gains rates. ISOs can trigger AMT. Typically granted only to employees.
**Key feature:** Options are worthless if the stock price is below the strike price ("underwater"). They have zero value at that point — unlike RSUs.
Concentration Risk
Single-position risk — usually employer stock from RSUs / ESPP / options. Common rule of thumb: above 25% of net worth, concentration risk dominates returns.
Above the typical 25% prudence threshold. Plan a multi-year reduction strategy.
Educational illustration — not financial advice. Math: @/lib/finance/investing.ts.
The decision framework at exercise
**When to exercise options:** - Early exercise (83(b) election): exercise immediately at grant, start the capital gains clock early. Maximum risk (you buy shares in a company that may fail) with maximum tax upside. - Exercise as you go: exercise a portion as you vest, managing the cash requirement and AMT exposure. - Exercise at liquidity: wait until IPO or secondary market — maximize clarity on value, but lose capital gains treatment on spreads taxed at ordinary income.
**When to sell RSUs after vesting:** Holding RSUs after they vest is equivalent to making a new investment decision to buy your company's stock at market price. If you would not buy that stock with fresh cash, you should not hold the vested shares. Concentrated employer stock is a significant risk.
Private vs. public company equity
Private company equity — options or RSUs — cannot be sold until a liquidity event (IPO, acquisition, secondary market sale). The 90-day post-departure exercise window on options is a critical deadline: if you leave before a liquidity event, you have 90 days to exercise any vested options or forfeit them. Early-stage companies often have high strike prices relative to valuations that never materialize.
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*Related: [Total compensation calculator](./total-compensation-calculator) — equity is one component of a full offer comparison. [Side income taxes](./side-income-taxes) — equity events can significantly affect your tax year.*
Frequently Asked Questions
what is the difference between RSUs and stock options
RSUs (Restricted Stock Units) are company shares granted directly—you own equity immediately upon vesting with no additional cost. Stock options give you the right to buy shares at a fixed strike price; you only own equity if you exercise. RSUs have simpler tax treatment; options offer more upside if stock price rises significantly above your strike price.
are RSUs or stock options better
RSUs are typically better for lower-volatility companies or risk-averse employees since you gain guaranteed equity. Stock options offer higher upside potential at high-growth companies but carry risk if the stock price falls below your strike. Your choice depends on company stability, risk tolerance, and market conditions.
how are RSUs taxed vs stock options
RSUs are taxed as ordinary income when they vest at fair market value, then as capital gains on future appreciation. Stock options may qualify for favorable long-term capital gains treatment (incentive options) or be taxed as ordinary income (non-qualified options), depending on type and holding period. Consult a tax professional to optimize your strategy.