Zero Hash calculates index values for a wide range of asset pairs. The official Zero Hash Daily Index value is the index value calculated and published at 4 pm Central Time, however, Zero Hash also calculates a continuous Real-time Index.
Zero Hash uses transaction data from a sample of top exchanges in its calculation. Those exchanges are Bitfinex, Bitstamp, Coinbase Pro, Gemini, HitBTC, Huobi Pro, itBit, Kraken and OKCoin.
For each exchange that has trading volume, we calculate the volume-weighted average price (VWAP) over the proceeding hour. We then take the arithmetic mean of this value across all exchanges. If there is no trading activity on any exchange during this period, we will utilize the last calculated index value.
For more information on the Index price rounding precision, please refer here Price Precision.