Prediction Market Index.
SF Index v2 by SimpleFunctions
Live volatility, geo risk, breadth, and activity across the prediction market tape.
The Prediction Market Index is a four-gauge market-wide state vector built from Kalshi and Polymarket. Disagreement is per-ticker realized volatility; geo risk is a curated geopolitical basket; breadth is up/down skew; activity is tape-wide percentile. One wake signal for agents, one monitor pane for desks. JSON API with 7-day history. Refreshed every 15 minutes.
Live history
Computed every 15 minutes. SF Index v2 history starts 2026-04-09.
Prediction market volatility, geo risk, breadth, activity.
Four gauges, each computed from a different slice of the prediction market tape. Disagreement is the prediction-market volatility component; the other three describe risk direction, move skew, and tape activity. Read together they describe regime; read individually they describe pressure points.
Disagreement
0–100Median per-ticker realized volatility over the last hour. The prediction market volatility component of the index. High readings = consensus unsettled, contracts repricing quickly.
Geo Risk
0–100Theater-equal weighted curated geopolitical basket. High readings = risk-signed contracts moving toward worse outcomes.
Breadth
−1 … +1Up/down skew of markets with absolute 24h net delta ≥ 10¢. Positive = tape moving up; negative = tape moving down.
Activity
0–100Percentile rank against trailing 30-day rolling windows. 50 is normal; >80 is an unusually active prediction market tape.
How agents use the index
Four numbers are a cheap wake signal. An agent on a 30-minute loop polls the index, decides whether the market state has shifted enough to refresh the full world, and saves tokens when nothing meaningful has moved.
How institutions use the index
A market-wide monitor for event risk and repricing pressure. Sits next to a VIX panel or a macro screen, not as a substitute. Hedging desks use it as a pre-screen before deciding which prediction-market contracts deserve attention.
How it differs from a stock index or volatility index
Underlying
Listed equity weights
SPX option implied vol
Event contract prices and movement
Update cadence
Realtime tick
Realtime tick
15-minute snapshot
Tradable?
Yes (futures, ETFs, derivatives)
Yes (VIX futures, options)
No — informational only
What it tells you
Equity beta direction
Forward equity volatility
Event repricing, geo risk, breadth, activity
Useful for
Equity exposure
Vol regime detection
Event-driven monitoring, agent wake signal
API access
Two endpoints. Both public, no auth, JSON. Latest snapshot is computed every 15 minutes; history endpoint serves snapshots since SF Index v2 launched 2026-04-09.
curl https://simplefunctions.dev/api/public/indexcurl https://simplefunctions.dev/api/public/index/history?days=7JSON schema
disagreementnumber/null0–100Median realized repricing across markets
breadthnumber/null−1 … +1Up/down skew of large 24h moves
geoRisknumber/null0–100Curated geopolitical risk basket
activitynumber/null0–100Market-wide activity percentile
componentsobject/nullmixedComponent details from the underlying computation
timestampstringISO datetimeSnapshot computation time
dataStartDatestringdateSF Index v2 history start (2026-04-09)
nextActionsobjectURLsSuggested drill-down endpoints
Example response
Compact, four numbers, timestamp, and pointers to the related world state and history endpoints. Example values shown — call the API for live values.
GET /api/public/indexJSON{
"disagreement": 52,
"breadth": 0.32,
"geoRisk": 31,
"activity": 57,
"timestamp": "2026-04-30T01:45:00.061Z",
"dataStartDate": "2026-04-09",
"nextActions": {
"drill": [
{ "method": "GET", "url": "https://simplefunctions.dev/api/public/index/history?days=7" }
],
"related": [
{ "method": "GET", "url": "https://simplefunctions.dev/api/agent/world?format=json" }
]
}
}FAQ
What is a prediction market index?
A prediction market index is a combined signal built from many prediction markets at once. Instead of reading one contract at a time, it summarizes broad repricing, risk, breadth, and activity across the market tape.
What is the SF Index?
The SF Index is the SimpleFunctions Prediction Market Index. It reports four gauges — disagreement, geo risk, breadth, and activity — computed every 15 minutes from Kalshi and Polymarket data.
Which markets are included in the index?
Active Kalshi and Polymarket contracts that meet liquidity and movement thresholds. Sports, weather, and very thinly traded markets are filtered out. The geo-risk basket is a curated set of geopolitical contracts weighted by theater.
How often is the index updated?
Every 15 minutes. The latest value is at /api/public/index and historical snapshots are at /api/public/index/history. SF Index v2 history starts 2026-04-09.
What does disagreement mean?
Disagreement (0–100) is the median per-ticker realized volatility over the last hour across qualifying markets. Higher means contracts are repricing quickly and consensus is unsettled.
Is this a prediction market volatility index?
Effectively yes for the disagreement gauge — it is a per-ticker realized volatility median across the prediction market tape. The other three gauges (geo risk, breadth, activity) capture risk direction, move skew, and tape activity. Together they give a richer regime read than a single volatility number.
How is the SF Index different from VIX or a stock volatility index?
VIX is implied volatility from S&P 500 options. The Prediction Market Index is realized movement and risk across event contracts on Kalshi and Polymarket. Different underlying, different cadence (15 minutes vs tick), and the SF Index is informational only — not tradable.
What does geo risk mean?
Geo Risk (0–100) is a theater-equal-weighted basket index over curated geopolitical contracts. Higher means risk-signed conflict and geopolitical contracts are moving toward worse outcomes.
What does breadth mean?
Breadth (−1 to +1) is the up/down skew of markets with absolute 24-hour net delta of at least 10 cents. Positive breadth means large moves are broadly upward; negative breadth means the tape is moving down.
What does activity mean?
Activity (0–100) is a percentile rank against trailing 30-day rolling windows. 50 is normal; readings above 80 mean an unusually active prediction-market tape.
Can AI agents use the index?
Yes. Agents can use the four numbers as a wake signal before fetching the full world state. Rising disagreement or activity tells an agent the market state has changed enough to re-check context.
Is the SF Index a tradable product?
No. The SF Index is an informational index and API, not a tradable fund, token, derivative, ETF, or investment product. It is also not equivalent to VIX or to a stock index.
Related surfaces
World State API for AI Agents
Use the index inside the full agent world state.
Prediction Market API
Market data, search, screeners, world state, and workflows.
Event Probability API
Query real-world events as structured probabilities.
Prediction Market Hedging
Use index pressure as a hedging pre-screen.
Prediction Market Screener
Filter markets by liquidity, yield, risk, and microstructure.
Prediction Market Data
Real-time and historical prediction market data surfaces.
Prediction Market Search API
Natural-language search across Kalshi and Polymarket.