Assignment, early exercise, dividends and taxes

Income strategies involve being short options, and being short options means the other side can act before you expect. This lesson covers the mechanics that surprise premium sellers: when early assignment actually happens, what dividends do to it, and the tax notes that change the arithmetic.

When early assignment happens

A long American option can be exercised any day, but a rational holder only does so when exercising is worth more than selling the option. That is when the option's extrinsic value is close to zero. So early assignment is:

• Very unlikely on an OTM option (it has no intrinsic value; exercising would be paying more than market).
• Unlikely on an ITM option with meaningful extrinsic value left.
• Likely on a deep ITM option near expiration, or one whose extrinsic value has been driven to zero by a dividend or interest.

Illustration. You are short the $45 call on XYZ. XYZ is $52. Two situations:

The rule for sellers: watch the extrinsic value of any short ITM option. When it approaches zero, expect assignment, and close or roll if you do not want it.

Dividends and short calls

A stock pays a dividend to whoever owns it at the close before the ex-dividend date. A call holder does not receive it. So a call holder who wants the dividend must exercise before the ex-date, and will do so if the dividend exceeds the call's remaining extrinsic value.

XYZ at $52, ex-dividend tomorrow, dividend $0.50. You are short the $45 call, price $7.10, extrinsic $0.10. The holder exercises tonight: they pay $0.10 of extrinsic to collect $0.50 of dividend. You are assigned, your shares are gone before the ex-date, and you do not receive the dividend either.

For a covered call writer this is rarely a disaster (you sold at a strike you agreed to) but it is a surprise if you had planned around the dividend, and it changes the tax picture (below).

Check: for any short call, if (dividend) > (extrinsic value) on the day before ex-date, assume assignment.

Puts, interest and early exercise

A deep ITM put holder receives cash on exercise, and cash today is worth more than cash at expiration when rates are meaningful. At a 5% rate, a $50 strike with 30 days left earns about $0.20 of interest; a deep ITM put with less extrinsic value than that is a candidate for early exercise. Same rule: extrinsic near zero, expect assignment.

What happens in your account

Short put assigned: you buy 100 shares per contract at the strike. The cash (cash-secured) or margin (otherwise) is used. You now hold stock and have full stock risk.

Short call assigned, covered: your 100 shares are sold at the strike. You have cash.

Short call assigned, not covered: you are now short 100 shares at the strike. This is a naked short stock position with unlimited risk and a margin requirement; most brokers require you to cover it promptly.

Spread, short leg assigned early: you hold the stock from the short leg plus the long leg. The max loss still holds if you sell or exercise the long option, but the stock position in between can need far more buying power than the spread did. Know your broker's policy before it happens on a Friday afternoon.

Key idea: Early assignment happens when a short ITM option's extrinsic value approaches zero, which dividends and interest can cause abruptly. Check extrinsic value on every short ITM option before ex-dividend dates and in the final week.

Tax notes

These are pointers for US taxpayers, not advice; rules vary and change, and your situation matters.

• Premium from expired short options is a short-term capital gain in the year of expiration, regardless of holding period.
• Premium from an assigned short put is not taxed separately; it reduces the cost basis of the shares you were assigned.
• Premium from an assigned short call is added to the proceeds of the share sale.
• Qualified dividend treatment requires holding the stock unhedged for a minimum period around the ex-date. Writing a deep ITM call against shares can break that, turning a qualified dividend into ordinary income. OTM calls generally do not.
• Long-term holding periods can be suspended by writing deep ITM calls against long-held stock (the "qualified covered call" rules); check before writing calls more than one strike in the money on shares with a large unrealised gain.
• Broad-based index options get Section 1256 treatment (60/40); equity and ETF options do not.
• Wash sales apply to options: closing a losing option and opening a substantially identical one within 30 days can defer the loss.

The recurring theme: option premium is mostly short-term, ordinary-rate income, so a 12% gross return can be noticeably less after tax than a buy-and-hold with long-term treatment. Run the after-tax number.

Why income is not free

Pulling the module together:

• A covered call and a cash-secured put are each a short put: paid to take the downside from a strike and give up the upside above it.
• The premium is small relative to the stock risk, often 1% to 2% of notional per month against 100% notional exposure.
• Early assignment can remove the position, the dividend, or both, at the least convenient moment.
• Taxes take a larger share of premium than of long-term stock gains.
• The strategies underperform holding in strong years and do not protect in bad ones; they win in the middle.

Someone who understands all that and still wants the middle of the distribution has a legitimate strategy. Someone who was told it was free money has a surprise coming.

Try it: For any stock with a dividend, find the next ex-date and the dividend amount. Look at the ITM calls expiring within two weeks after the ex-date and compute the extrinsic value of each. Mark which ones would be assigned the day before the ex-date if you were short them.

Recap

• Early assignment is likely when a short ITM option's extrinsic value is near zero; OTM options are almost never assigned early.
• Before an ex-dividend date, a short ITM call with extrinsic value below the dividend will usually be assigned.
• Deep ITM puts can be exercised early when interest on the strike exceeds the extrinsic value.
• Assignment on a spread's short leg leaves you with stock plus the long leg; buying power, not max loss, becomes the problem.
• Option premium is generally short-term income for tax, and ITM calls can affect dividend and holding-period treatment; run the after-tax number.