Accounting
The trade is closed and the cash is in, so the profit should be beyond argument. It rarely is.
Realised P&L sounds like the one number that should be beyond argument — the trade is closed, the cash is in. In practice it is where reconciliations most often fail, because "what did I actually make" depends on lot-matching rules, a contract multiplier, and whose figures you trust for derivatives.
Sell part of a holding built over time and something must decide which shares left. FIFO — first in, first out — matches each sale against your earliest open lots. It is the common default and the one most brokers report.
Neither is wrong. But mixing methods across venues, or against your broker's reporting, guarantees numbers that never tie out.
Options are quoted per share and traded per contract of 100. Miss the multiplier and every option line is off by two orders of magnitude:
option P&L = (exit price − entry price) × 100 × contractsObvious stated plainly, and still one of the most frequent errors in hand-built tracking — usually because a CSV export lists per-share prices and the multiplier is applied inconsistently.
Selling to open means you profit when you buy back lower. Applying the long convention to a short leg flips the sign on every premium-selling trade you have ever made. For a short option the realised figure is entry minus exit, times the multiplier — and an option that expires worthless realises the full premium with no closing trade at all, which is exactly the row that tends to go missing.
Three closes that produce no closing trade, and therefore no obvious row to record:
Expired worthless. Short option realises the entire premium. Nothing arrives from the venue to tell you.
Assigned on a short put. The option is not realised as a gain in isolation — it converts into a stock lot. The premium properly reduces the basis of the shares you now hold.
Called away on a short call. The shares are sold at the strike. Realised P&L is strike minus share basis, and the call premium is separate income.
These conversions are why option and stock P&L cannot be reconciled in isolation. A cycle that starts as an option and ends as stock has to be followed across the transition or the premium ends up in one bucket and the shares in another.
For perps and similar, do not re-derive P&L with FIFO. Funding payments, mark conventions and fee treatment vary by venue, and any independent reconstruction will disagree with the account you are checking against. Use the venue's own realised figure so your total is reconcilable against its interface. Consistency with the source beats theoretical purity.
One lot-matching method applied everywhere. The ×100 multiplier on every option line. Correct sign convention for shorts. Expiries and assignments recorded even though nothing traded. Venue-reported figures for derivatives. Fees handled consistently — and stated, since most quick calculations quietly omit them.
None of it is difficult. It is just unforgiving: any single one of those omitted produces a total that looks plausible and is wrong, which is considerably worse than one that is obviously broken.
First in, first out: each sale is matched against your earliest open lots. It is the common default and what most brokers report, and it determines both realised profit and the basis carried forward.
The ×100 contract multiplier is missing. Options are quoted per share and traded per 100-share contract, so every option line needs it applied.
A short option that expires realises the full premium, even though no closing trade occurs. It has to be recorded deliberately — nothing arrives from the venue to prompt it.
It is a conversion, not a realisation. The short put becomes a stock lot, and the premium collected properly reduces the basis of those shares.
No. Funding, mark and fee conventions differ by venue, so use the venue's own realised figure. That keeps your total reconcilable against the account you are checking.
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Open the live demo — no signupEducational only. Nothing here is investment, financial, legal or tax advice, and none of it is a recommendation to trade. Figures are worked examples, not forecasts. Verify against your broker before acting.