Why your option shows a profit but selling could lose money

Start with what the displayed P/L measures

Before treating a green P/L number as money you could collect, identify the price behind it. Then compare your actual entry cost with a possible exit price, including fees.

This guide considers a purchased, single-leg option that is later sold to close. Every quote and fee below is invented for illustration. None is a current market quote, a broker’s fee schedule or a trading recommendation.

A platform’s ‘mark’ is a valuation input. Check the platform’s definition: do not assume every mark uses the midpoint or every P/L display includes the same charges.

When the mark does equal midpoint, it averages the bid and ask. It does not show an agreed sale price. The Options Industry Council explains how bids, offers and available size form the quote, and why order execution can differ from an expected price.

Keep these three figures separate:

• Midpoint movement: how the average quote changed between observations.
• Marked P/L: current valuation minus actual purchase cost, using the display’s stated convention.
• Realized P/L: actual sale proceeds minus actual purchase cost and included charges.

FINRA distinguishes paper gains from gains realized through closing a position. A changing account display does not itself complete a trade.

Worked example: a higher midpoint, a losing sale

Assume two contracts, a premium multiplier of 100, unchanged contract terms and a position closed before expiration. All amounts are in US dollars.

At entry, the bid is $1.90 and the ask is $2.10, so the midpoint is $2.00. A hypothetical purchase of two contracts at $2.10 costs $420 before charges: $2.10 × 2 × 100.

Later, the bid is $2.05 and the ask is $2.35, so the midpoint is $2.20. The midpoint rose $0.20, or 10% of the original $2.00 midpoint.

At a $2.20 mark, the position is valued at $440. Compared with its actual $420 purchase cost, midpoint-based P/L shows a $20 gain before fees.

A hypothetical sale at the $2.05 bid returns $410. That is a $10 gross loss: $410 − $420 = −$10.

Now assume an invented charge of $0.65 per contract on each side and no other charges. Entry charges are $1.30 and exit charges are $1.30, for $2.60 total. The net result is $410 − $420 − $2.60 = −$12.60.

The midpoint rose 10%, and midpoint-based P/L showed a gain. Neither made the assumed sale profitable. The example also assumes the displayed bid covers the full quantity and remains available until execution; real fills may differ.

Why changing spread width matters

The entry spread was $0.20; the later spread was $0.30. Buying at the entry ask put the purchase $0.10 above its midpoint. Selling at the later bid put the sale $0.15 below its midpoint. Together, those differences total $0.25 per quoted unit.

The $0.20 midpoint increase did not cover that $0.25. For an ask purchase followed by a bid sale, under the stated assumptions:

Gross P/L = [change in midpoint − half the entry spread − half the exit spread] × contracts × multiplier

[$0.20 − $0.10 − $0.15] × 2 × 100 = −$10.

This is an accounting identity under the stated fill assumptions, not a model that predicts prices. It also explains why subtracting two full spreads would overstate the midpoint-relative cost. The relevant difference here is half of each observation’s spread.

Keep the entry purchase at $2.10, the later midpoint at $2.20, two contracts and a 100 multiplier. Compare three hypothetical exit spreads, with the same $2.60 total charges:

These are three separate scenarios, not a forecast. The midpoint is identical in all three; the assumed sale results are different.

Calculate the sale price needed to cover your cost

Once an order has filled, use the actual entry price rather than the old midpoint.

Fee-aware break-even sale price = entry fill price + total entry and exit charges ÷ (contracts × multiplier)

$2.10 + $2.60 ÷ 200 = $2.113.

That is an arithmetic threshold, not necessarily a valid order price. Check the contract’s permitted price increment. If this hypothetical contract allowed one-cent ticks, $2.12 would be the lowest permitted price above the threshold. A full fill there would give ($2.12 − $2.10) × 200 − $2.60 = $1.40 after charges.

A $2.12 sell limit would establish a minimum sale price; it would not guarantee a buyer. The SEC explains that a sell limit executes only at its limit or higher. OIC notes that a limit order may never execute.

This is a break-even option sale price before expiration. It is not the underlying stock’s expiration break-even, and it is not a reason to hold a position until the threshold is reached.

An exit-price worksheet to use before entering

Record the exact strike, expiration and call or put, then work through these six checks:

1. Entry assumption: ask, midpoint or limit? An unfilled limit is an assumption; replace it with the actual fill once available.
2. Valuation convention: which price does the tool or broker use for P/L, and are fees included?
3. Exit scenarios: choose a hypothetical future midpoint and more than one spread, then calculate the implied bids. Do not silently reuse today’s spread.
4. Dollar result: sale proceeds minus entry cost minus charges. A target midpoint is not a net return.
5. Quantity and timing: record the quote timestamp and compare bid size with intended quantity. An old quote or displayed size does not guarantee a later fill.
6. Decision boundary: if an order remains unfilled or the quote changes, recalculate before changing the limit. A marked gain does not justify a new execution assumption.

Large volume or open interest cannot supply the missing exit price. OIC’s liquidity discussion emphasizes quoted width and size, rather than a guarantee from activity counts. For that separate distinction, see volume versus open interest.

Check the quote arithmetic, then keep the scenarios separate

The spread cost calculator checks width, midpoint and hypothetical spread dollars for one quote at a time. It does not forecast an exit quote, combine two observation times into P/L or include fees. Keep the entry-and-exit worksheet alongside it.

For basic quote definitions, see the options bid-ask spread guide.

These calculations assume an unchanged premium multiplier. OCC specifies a 100 multiplier for standard equity-option premiums and notes that corporate actions can alter contract terms. Verify the actual contract rather than assuming every option is standard.

Partial fills, changing quotes, unavailable size, additional charges and different execution prices can change the result. The examples exclude taxes, exercise, assignment and multi-leg positions. A correct cost calculation does not establish fair value, predict a favorable move or remove the risk of loss.

ConvexRadar is research software, not financial advice. Options involve risk and are not suitable for all investors. Read OCC’s Characteristics and Risks of Standardized Options before trading.

Prepared with AI assistance. Market-mechanics statements were checked against the linked primary sources. All numerical examples are original, hypothetical calculations with stated assumptions.