Implied probability and expected move · Demo

A year of SPX implied cones against realised outcomes

Recorded in cvforge on July 7, 2026 by ConvexValue · Published July 25, 2026

Realised against implied probability cones for SPX out to a year, long enough for the volatility risk premium to show up as a pattern rather than a coincidence.

Exact prompt

Give me a dashboard that lets me analyze realized vs implied probability cones for $SPX for the next 1 year.

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

Runs on the free cvforge app and the free data tier (20 requests/hour). No card needed.

Fields used

implied_volatility, delta, strike_price, expiration_date, underlying_price, fair_market_value

How to read it

Extending the comparison to a year is what makes the premium legible. Over short windows the gap between implied and realised is noise; over a year, index options priced consistently above what the index delivered is the well-documented volatility risk premium.

Two cautions. A one-year cone rests on long-dated implied volatility, which is thinly traded and moves slowly, so the band is coarse. And a single year is one observation of a cycle — the premium’s existence is a broad finding, its size in any given year is not.

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.
  • These are risk-neutral probabilities implied by option prices, not forecasts. They shift with volatility as much as with expectations.
  • Anything derived from implied volatility inherits the model behind it; treat the numbers as a market-implied range, not a measurement.

Related demos

Search focus: spx implied vs realized cone one year. Related: index volatility risk premium chart, year ahead spx probability cone. Originally posted on X.