Strike prices for stock options are determined two very different ways depending on the type of option. For exchange-traded options on a public stock, the exchanges themselves set the available strike prices at standardized intervals tied to the underlying stock’s price. For employee stock options, the strike price is anchored to the fair market value of the company’s stock on the date of grant: the closing price for a publicly traded employer, and an independent 409A appraisal for a private one.
How Exchanges Set Strikes for Listed Options
Open an options chain for any publicly traded stock and you’ll see strike prices arranged at regular intervals. Nobody picks those numbers arbitrarily. The listing exchanges follow formal rules that tie the spacing between strikes to the current price of the underlying stock. Cheaper stocks get tighter intervals so traders can place more precise bets; expensive stocks get wider spacing to keep the number of listed contracts manageable.
The general framework: for stocks priced at $25 or below, strike price intervals can be as narrow as $2.50. As the price rises, intervals widen to $5.00 or more.1SEC. Cboe EDGX Options Exchange Rules Many actively traded names participate in a $1 Strike Price Program that permits $1 intervals for stocks under $50, giving traders finer granularity.2Nasdaq. ISE Options 4 – Options Listing Rules
Weekly options, which expire within days or weeks rather than months, use their own interval table. Spacing depends on both the stock’s price and its average daily trading volume. A stock priced between $25 and $75 with high trading volume might carry $1 intervals on its weekly options, while the same stock at low volume would use $5 intervals.3SEC. NYSE American Rules – Rule 903 Series of Options Open for Trading Long-dated LEAPS follow the same specifications as standard options apart from their longer expirations. Initial LEAPS strikes are generally set within 25% above or below the stock’s current price.4The Options Clearing Corporation. Long Term Equity Anticipation Securities (LEAPS)
As the underlying moves, exchanges add new strikes to keep a useful range of in-the-money and out-of-the-money contracts available. Under exchange rules, new series can be opened when the market price moves more than five strike prices away from the original set.2Nasdaq. ISE Options 4 – Options Listing Rules Every trader sees the same standardized menu, which keeps the market liquid and transparent.
How Employee Stock Option Strike Prices Are Set
Employee stock options work in a completely different world. There is no menu. There is one price, and federal tax law sets the floor.
For incentive stock options (ISOs), the Internal Revenue Code requires that the strike price be at least equal to the fair market value of the stock on the date the option is granted.5Office of the Law Revision Counsel. 26 USC 422 – Incentive Stock Options This isn’t a best practice. If the strike falls below fair market value, the option fails to qualify as an ISO at all, and the favorable tax treatment goes away.
Non-qualified stock options (NSOs) face a parallel rule. Section 409A of the Internal Revenue Code governs deferred compensation and treats a below-market-value option as deferred compensation carrying harsh penalties.6Office of the Law Revision Counsel. 26 USC 409A – Inclusion in Gross Income of Deferred Compensation Under Nonqualified Deferred Compensation Plans The practical result: ISOs and NSOs are almost always priced at exactly 100% of fair market value on the grant date. The company’s board of directors formally approves the strike price through a board resolution, typically relying on a compensation committee’s recommendation and an independent valuation.
How Fair Market Value Is Determined
For a publicly traded company, fair market value is the stock’s closing price on the grant date. No ambiguity, no special report; the market provides a real-time answer.
Private companies have a harder problem, because their shares don’t trade on any exchange. To establish a defensible fair market value, most private companies hire an independent appraiser to produce a 409A valuation. The Treasury regulations specify the factors the appraiser must weigh: the company’s tangible and intangible assets, projected future cash flows, the value of comparable public companies, recent arm’s-length transactions involving the company’s stock, and control premiums or marketability discounts.7IRS. Internal Revenue Bulletin 2007-19 Using an independent appraisal that meets these requirements creates a legal safe harbor: the IRS will presume the valuation is reasonable unless it can affirmatively prove otherwise.
A 409A valuation doesn’t last forever. It expires after 12 months, and the company must get a new one before granting more options.7IRS. Internal Revenue Bulletin 2007-19 More importantly, the valuation goes stale immediately if a material event changes the company’s value before the 12 months are up. Closing a new funding round, a sharp swing in revenue, signing a term sheet for an acquisition, or losing a key executive can all invalidate the existing valuation and force an update. Granting options off an outdated valuation exposes employees to serious tax risk.
These appraisals typically cost between $500 and $15,000, depending on the complexity of the company’s capital structure and whether expedited delivery is needed. Early-stage startups with simple cap tables land at the lower end. Later-stage companies with multiple share classes, convertible notes, and complex waterfall provisions pay considerably more.
The 10% Shareholder Exception
If you own more than 10% of the total voting power of your employer’s stock, the rules tighten. An ISO granted to a 10% shareholder must carry a strike price of at least 110% of fair market value, not the standard 100%. The option also cannot be exercisable more than five years after grant, compared with the standard ten-year window.5Office of the Law Revision Counsel. 26 USC 422 – Incentive Stock Options Miss these conditions and the option simply doesn’t qualify as an ISO.
The 10% threshold is easier to hit than most people expect, because the tax code counts shares owned by your spouse, siblings, parents, grandparents, and children as yours for this calculation.8Office of the Law Revision Counsel. 26 USC 424 – Definitions and Special Rules Stock held indirectly through partnerships, trusts, or other entities also gets attributed proportionally. A founder who personally owns 7% may cross the line once family shares and a family trust are added in.
What Happens if the Strike Price Is Set Too Low
Getting the strike price wrong on employee stock options isn’t a paperwork problem. For NSOs, Section 409A imposes a three-part penalty on the option holder if the strike is below fair market value at grant. First, the value of the option is included in the employee’s gross income immediately or upon vesting, whichever is later. Second, the employee owes an additional tax equal to 20% of the compensation amount. Third, interest accrues on the underpayment at the IRS underpayment rate plus one percentage point, retroactive to the year the compensation was first deferred.6Office of the Law Revision Counsel. 26 USC 409A – Inclusion in Gross Income of Deferred Compensation Under Nonqualified Deferred Compensation Plans The penalty hits the employee, not the company, which is why employees at startups should care whether the board used a current 409A valuation.
For ISOs, the consequence is different but still painful. A below-market strike disqualifies the option as an ISO.5Office of the Law Revision Counsel. 26 USC 422 – Incentive Stock Options It gets treated as an NSO instead, so the entire spread between the strike and the stock’s value at exercise is taxed as ordinary income rather than qualifying for the more favorable capital gains treatment ISOs can provide.
How the Strike Price Can Change After the Grant
Once set, a strike price stays fixed unless a corporate event changes the structure of the underlying shares. Stock splits, reverse splits, and large special dividends all require proportional adjustments to preserve the economic value of existing contracts.
The math is straightforward. In a 2-for-1 stock split, the strike price is cut in half and the number of contracts doubles. A $100 strike becomes $50, and one contract covering 100 shares becomes one contract covering 200 shares. Reverse splits work the same way in the other direction. The Options Clearing Corporation handles these adjustments for listed options using standardized formulas established under its bylaws.9The Options Clearing Corporation. Worksport Ltd Reverse Split Option Adjustment
Mergers and Acquisitions
When a company gets acquired, the treatment of outstanding stock options depends on the deal terms. In an all-stock acquisition, unvested options in the target company are commonly converted into unvested options in the acquiring company, with the strike price and vesting schedule adjusted to reflect the exchange ratio. Vested options may be converted into the acquirer’s options or cashed out at the difference between the strike price and the deal price.
Every acquisition is different, and the specific treatment is spelled out in the merger agreement. Some deals accelerate vesting for all outstanding options. Others cancel underwater options, where the strike price exceeds the deal price, for no payout at all. If you hold options in a company being acquired, the acquisition documents and any communication from your employer are the only reliable source for what happens to your grants.