How is the index price for a perpetual contract compiled?

Index Price Composition

1. The index price for a perpetual contract is derived from the weighted average of spot prices across multiple major cryptocurrency exchanges. These exchanges are selected based on trading volume, liquidity, and regulatory compliance.

2. Each exchange contributes a spot price feed that undergoes real-time validation to filter outliers and detect anomalies such as flash crashes or manipulation attempts.

3. Weighting coefficients are dynamically adjusted every 30 seconds to reflect current exchange volumes, ensuring higher-volume venues exert proportionally greater influence on the final index value.

4. The raw data is normalized to a common base currency—typically USD—and converted using stablecoin-based pairs where direct fiat pairs are unavailable.

5. A median filter is applied after weighting to suppress short-term volatility spikes before the final index price is published.

Data Source Selection Criteria

1. Exchanges must maintain a minimum 30-day average daily trading volume exceeding $500 million in BTC/USD or ETH/USD equivalent pairs.

2. Only exchanges with documented custody practices, proof-of-reserves attestations, and at least two independent third-party security audits are eligible.

3. Geographic distribution is enforced: no single jurisdiction may contribute more than 40% of the total index weight to mitigate regional regulatory shocks.

4. Spot price feeds must be delivered via TLS-encrypted WebSocket connections with sub-100ms latency guarantees; delayed or unauthenticated feeds are discarded immediately.

5. Historical uptime of each exchange’s API must exceed 99.95% over the prior 90 days to remain in the index basket.

Real-Time Anomaly Detection

1. A deviation threshold of ±1.8% from the 5-second moving median triggers an automatic hold on that exchange’s contribution for up to 60 seconds.

2. Cross-exchange correlation analysis identifies coordinated price movements inconsistent with order book depth or trade size distributions.

3. Volume-weighted bid-ask spread monitoring flags venues where spreads widen abnormally without corresponding market-wide volatility.

4. On-chain transaction flow data is cross-referenced to detect mismatches between exchange-reported volume and actual blockchain settlement patterns.

5. Any single exchange contributing more than 22% deviation from the consensus index for three consecutive seconds is temporarily excluded from the calculation.

Funding Rate Interaction

1. The index price directly anchors the funding rate formula, which determines periodic transfers between long and short positions.

2. Funding intervals are fixed at eight-hour cycles, and the index value sampled at cycle initiation remains immutable for that period’s settlement.

3. If index updates fail for more than four consecutive sampling points, the system falls back to a time-weighted average of the last five valid index readings.

4. Funding payments are calculated exclusively using the official index—not internal mark price or exchange-specific indicative values.

5. During extreme market stress, the funding cap mechanism activates only when the index diverges from the mark price by more than 3.5% for over 120 seconds.

Common Questions

Q: Can an exchange be removed from the index outside of the quarterly review cycle?A: Yes. Immediate removal occurs if an exchange suffers a confirmed hot wallet breach, fails a mandatory reserve audit, or exhibits sustained API failure exceeding 0.1% error rate over 15 minutes.

Q: How often is the index recalculated?A: The index price is refreshed every 100 milliseconds using overlapping 5-second sliding windows of validated spot data.

Q: Is the index price affected by futures or options markets?A: No. The index relies solely on spot market data. Derivatives order books, open interest, or implied volatility surfaces play no role in its computation.

Q: What happens if two exchanges report identical prices for over 30 seconds?A: That pattern triggers a duplicate-source alert. The system suspends both feeds and reverts to the remaining qualified sources while initiating forensic timestamp analysis.