Spot Index Calculation Rules:
1. Every second, the latest quotes of all components in the index are collected.
2. The median value (or average value, as applicable) of the exchange index components is used to determine the spot price index.
3. When the component count for calculating the index is even, the average of the two middle values is used. If there are an odd number of components, the median value is used.
Example A:
For BTC, suppose the prices taken for the index are from KuCoin, Binance, and OKX. At a point in time, the collected prices are 40,000 USDT, 41,000 USDT, and 39,000 USDT each. As there are an odd number of components (three), the median value is used. As such, the spot index price for BTC is 40,000 USDT.
Example B:
Suppose that this time, for BTC, the prices taken for the index are from KuCoin, Binance, OKX, and Coinbase. At a point in time, the collected prices are 40,000 USDT, 41,000 USDT, 39,000 USDT, and 42,000 USDT each. As there are an even number of components (four), the average of the middle two values is used. As such, the spot index price for BTC is: (40,000 + 41,000) ÷ 2 = 40,500 USDT.