A Short Put Can Lose at November Expiration's Max Pain

A stock finishing at a chain's “max pain” level can still leave a put seller with a loss and a substantial share purchase. The number minimises an aggregate option-value calculation. Your strike, premium and resulting shares determine your own outcome.

That distinction is useful during 13–19 November, ahead of the Friday, 20 November 2026 standard monthly expiration shown in the Cboe expiration calendar. Before treating a positioning level as a reason to leave a short option open, calculate what happens to that particular contract at the level.

The example below uses an entirely fictional stock and chain. It supplies no current max-pain estimate, price target or recommended trade for November.

What the minimum measures

For this calculation, take one expiration and hold its open-interest counts fixed. At each candidate stock price, multiply every call's intrinsic value by its open interest and contract multiplier. Do the same for puts, then add the amounts. The candidate price with the lowest total is the max-pain level under this method.

Open interest supplies outstanding contract counts. The Options Industry Council's open-interest explanation describes how OCC calculates them using opening and closing trades, with exercised contracts removed. The earlier SPX volume and open-interest article explains why a day's trading volume cannot replace that position count.

The calculation contains no entry premiums. It cannot tell us the holders' combined profit or loss, which would require their acquisition costs and other cash flows. Nor does it identify who owns the options, their other positions, or the hedges they may change before expiration. A minimum in this calculation provides no probability that the stock will finish there.

A fictional chain with a $100 minimum

Assume these are all the options in a fictional 20 November chain. Each is a standard, unadjusted contract for 100 shares, with the same expiration and valuation time. Counts remain unchanged throughout the example.

At a $100 stock price, the ten $90 calls each have $10 of intrinsic value per share. Their aggregate intrinsic value is $10,000. The ten $110 puts contribute another $10,000. Every other option has zero intrinsic value at that price.

Applying the same arithmetic gives:

The minimum is $100. The $109 row is an additional scenario between listed strikes. These dollar totals measure intrinsic value, not gross share-purchase payments or cash settlement by a clearing house. Physical exercise transfers shares against strike-price cash.

The short $110 put still loses $800

Now consider a trader short one of those $110 puts, with an invented original premium of $2 per share, or $200. At a $100 stock price, the put's intrinsic value is $1,000. Its expiration economic result is:

$200 premium − ($110 strike − $100 stock price) × 100 = −$800

If assigned, the trader pays $11,000 and receives 100 shares worth $10,000 at the assumed valuation price. The $200 premium reduces the economic loss to $800. It does not remove the $11,000 purchase obligation. The account also needs broker approval for writing the short put. Cash or permitted margin must meet the broker's funding requirements; margin can add financing costs and liquidation risk.

At $109, the same put has $100 of intrinsic value, giving a $100 profit after the original premium and before costs. The chain's aggregate value is then much higher, at $110,000. The put seller's result improves even though the aggregate payout moves away from its minimum.

Both results exclude commissions, exchange fees, spreads, financing and tax. They value any assigned shares at the stated stock price without assuming a sale there. Subsequent share-price changes create further gains or losses. If the stock falls to zero, the fully funded short put's loss is $10,800 before costs.

The position check for 13–19 November

For an actual 20 November holding, record the open-interest observation date, exact expiration, strike, multiplier and deliverable before using a displayed level. A snapshot can change as positions close or exercise. Keep adjusted contracts and other expirations outside a standard 100-share calculation unless their terms are explicitly modelled.

Then calculate your own result at that level and at adverse prices. Check the current closing bid and ask, displayed size and the broker's trading and exercise deadlines. The liquidity guide explains why an analytical value cannot promise an executable exit.

An American-style short option can be assigned before expiration. OIC's assignment FAQ also explains why the short holder cannot control the exercise decision and why broker procedures matter. The earlier pin-risk article covers uncertainty near a strike. A max-pain estimate supplies no protection against that uncertainty.

Under OCC's exercise-by-exception procedure, expiring equity options at least $0.01 in the money are generally exercised unless contrary instructions are given. The test uses the underlying's closing reference price, not a price from a later trading session. Customer automatic-exercise procedures and instruction cutoffs are broker-specific; holders should communicate their intentions to their broker. If $100 is the applicable closing reference price, the fictional $110 put is $10 in the money. Expiration processing can therefore create the $11,000 purchase obligation without a fresh exercise instruction, although assignment to this writer remains conditional.

This example concerns physically settled stock options. Cash-settled index options require their own settlement value and final trading time; the monthly calendar label alone cannot establish either. For a stock-option holder, the practical record to complete before the final session is the cash and shares each still-open leg can create, including whether the account can carry them after expiration.

Disclosure: Options Matrix Pro makes options-analysis software. General education, not financial advice. See our disclaimer.