An Option Gain Faces Two Tests for Net Investment Income Tax

A fictional investor buys a call for US$2,000 and later sells it for US$8,000. The US$6,000 gain enters the annual tax record. Whether the US Net Investment Income Tax adds another charge depends on the investor's wider income, even though the option trade is identical.

For an individual covered by the general rule, the 3.8% tax applies to the smaller of net investment income and the amount by which modified adjusted gross income exceeds the filing-status threshold. A portfolio estimate therefore needs both figures. Applying 3.8% to every option sale receipt would use the wrong starting amount.

This article concerns a US citizen investing personally in a taxable account. It explains a general federal mechanism with invented figures, not a reader's tax liability. Retirement accounts, businesses, trusts, nonresident status, special elections, straddles and Section 1256 contracts are outside the worked example.

Establish the gain before testing the threshold

IRS Publication 550 says that selling an option produces a capital gain or loss when the underlying property is, or would be, a capital asset in the holder's hands. For a purchased call sold before exercise, the gain starts with sale proceeds less cost, subject to the applicable adjustments.

Assume the fictional investor buys one fully paid, unadjusted Alder Co. call covering 100 shares, paying US$20 per share. The investor sells the same contract to close for an assumed US$80 per share before expiration in tax year 2026. The stock would be a capital asset. There are no other capital transactions, loss carryforwards, fees, currency changes or adjustments in the model.

The opening cost is 100 × US$20 = US$2,000. The closing receipt is 100 × US$80 = US$8,000. Subtracting the cost leaves US$6,000. The receipt includes US$2,000 of returned cost; it is not US$8,000 of gain.

The position is closed in this illustration. An exercised call would create a different stock and basis record, and a written option would require its own analysis. OMP's December put-premium example explains why an opening cash credit alone cannot establish a writer's recognised gain or its year.

Income above the threshold can limit the charge

The IRS NIIT overview lists a US$200,000 threshold for single filers and heads of household, US$250,000 for married joint filers and qualifying surviving spouses, and US$125,000 for married separate filers. Net investment income generally includes capital gains. NIIT is an additional tax; calculating it does not calculate regular federal income tax.

Now place the same US$6,000 option gain beside three different fictional wage totals. Assume a single US citizen, no other income, no relevant deductions or adjustments, and that NIIT modified adjusted gross income equals wages plus the gain. The US$6,000 is also the entire net investment income in each case. These assumptions deliberately remove the complications of a real return.

In Case B, US$3,000 × 0.038 = US$114. In Case C, the US$6,000 investment-income figure limits the tax base even though income exceeds the threshold by US$11,000. These are fictional NIIT calculations only. They omit regular federal tax, state and foreign taxes and any payment-timing calculation.

The IRS questions and answers distinguish wages from net investment income. Wages can nevertheless affect the other side of the calculation through modified adjusted gross income, as these assumptions show. The IRS also says the individual thresholds are not indexed for inflation.

That makes the whole-year record relevant to an options review. The same closing trade can produce different NIIT results in different households. A broker's trade-level profit figure cannot supply the missing income information.

Use the income definition for this particular tax

NIIT modified adjusted gross income has its own rules. The IRS FAQ describes adjustments involving foreign earned income and certain foreign-company or fund interests. Residency and some elections can also change the analysis. This example does not apply merely because someone trades US-listed options from Australia or another country.

The 2025 Form 8960 instructions start the disposition-gain calculation with amounts from a properly completed return and provide further adjustments. A single winning contract cannot replace annual netting, loss treatment and the applicable deductions. The current Form 8960 developments page and the instructions for the relevant tax year need checking before filing; the available instructions at preparation were labelled 2025.

Likewise, a gain's inclusion in one income measure cannot establish its treatment under another rule. OMP's IRA contribution-room article examines compensation for contributions, a separate question from NIIT. The calls and puts guide explains the underlying contract rights.

Keep the investment and payment plans workable

Liquidity requires its own allowance. An option's displayed value may not be available at an executable closing price. The model assumes a completed sale at US$80; it does not predict a fill. Bid-ask costs and fees reduce the investment result and need appropriate treatment in the actual records.

Concentration remains a separate portfolio decision. A profitable call on one company supplies no evidence that a larger position, repeated purchases or the rest of the household's exposure is suitable. The tax calculation places no ceiling on the economic damage a concentrated portfolio can suffer.

Time horizon also matters. The example ends before expiration, whereas a real call can expire without value. Changing an exit date for tax reasons leaves the contract exposed to stock-price, volatility and time-value changes during the extra holding period.

Funding suitability starts with the ability to lose the full call premium. Exercising a physically delivered call would additionally require arrangements for the strike-price purchase; this example avoids exercise and creates no assignment obligation for its call buyer. Writing options introduces different obligations. Neither a possible tax result nor an assumed future sale supplies that funding.

The IRS says NIIT is subject to estimated-tax provisions. Qualified review should establish any withholding or payment requirement separately from deciding whether cash can be reinvested. This article proposes no payment amount, deadline, tax election or trade for a reader.

Sources and scope

Sources were checked on 7 November 2026 Australia/Brisbane. The IRS materials above support the general US federal rules. Every company, option price, wage total and worked result is fictional author arithmetic. No market quote, model valuation, expected return or personal experience is claimed.

Options Matrix Pro publishes this article and has a commercial interest in its options-research platform. The linked OMP resources are first-party education. OMP does not prepare a tax return, determine tax residence or establish personal suitability. This is general education, not personal financial, investment, legal, retirement, accounting or tax advice. Options involve risk and are not suitable for every investor. Review your broker's requirements and the current standardised-options risk disclosure before trading.

Before committing a realised option gain to another use, retain its cost and closing record alongside the annual net-investment-income calculation and the correct modified-adjusted-gross-income calculation. Have the complete record reviewed before treating the closing cash as available after tax.