Payoff diagrams and P&L · Demo

A month of P&L on an SPX 7300–7400 strangle

Recorded in cvforge on June 25, 2026 by ConvexValue · Published July 25, 2026

The realised profit and loss of one specific SPX December strangle over the past month, priced from daily option history rather than a model.

Exact prompt

I want to chart the historical pnl for the past month of an $SPX dec 18 2026 7300-7400 strangle

Data cadence

Live U.S. option snapshots, refreshed through the session. Open interest is an end-of-previous-day figure and updates once daily.

Plan requirements

Needs the Research data plan, which adds end-of-day historical options aggregates. The rest of the build runs on the free tier.

Fields used

fair_market_value, strike_price, expiration_date, contract_type, break_even_price, implied_volatility, delta

How to read it

Note how specific the prompt is: an underlying, an expiration, both strikes, a window. That precision is what lets the build price the actual contracts each day instead of approximating the structure.

The line is a mark-to-market path, not a trading record. Each day’s value comes from that day’s end-of-day marks, so it shows an aggregate valuation path, not what you could have closed it for. Executable markets and transaction costs are not included.

Change it

The prompt is the interface. Ask for a different ticker, a different expiration window, or an extra column in the same sentence style and the agent edits the app in place — you do not start over, and you do not wait for anyone to build it.

Limitations

  • Snapshot data, not a transaction tape: the build reads the chain as it stands, so it cannot attribute a trade to a buyer or a seller.
  • Open interest updates once a day, so an intraday volume/OI comparison is always this session’s volume against yesterday’s open interest.
  • Contract coverage is U.S. listed equities, ETFs and indices. Indices use the I: prefix, for example I:SPX.
  • Current per-contract valuation is Massive fair market value (FMV), a proprietary estimate. cvforge does not provide option bids, asks, midpoint, quote sizes, NBBO or last trades, and FMV is not an executable quote.
  • Payoffs use Massive fair market value estimates. FMV is not an executable price, so premiums, P&L and break-evens are theoretical.
  • Curves before expiration depend on an implied-volatility assumption held constant; in practice volatility moves with price.

Related demos

Search focus: historical pnl of an options strangle. Related: spx strangle pnl chart, track option position performance history. Originally posted on X.