What is a spot index price?
OKX's USDT-margined contracts are denominated in USDT index price while coin-margined contracts are denominated in the underlying cryptocurrency's USD index price. To ensure the index prices accurately reflect each token's fair spot price, they are calculated as weighted averages of prices taken from at least 3 mainstream exchanges, plus additional measures for exceptional circumstances. We will make sure the index price fluctuates within a normal range even when its price is extremely volatile in a single exchange.
The makeup of some USDT trading pair's spot index price are as follows.
For more details, please visit OKX Price Index.
Calculating the spot index price
A. For each index price, retrieve the corresponding trading pair's price and volume from the designated exchanges in real-time.
B. Exchanges that underwent system maintenance or didn't update their latest price and volume during a specified time period won't be taken into calculation for the latest price updates. The update frequency is different for each index.
C. For trading pairs quoted in BTC, the prices will be converted to USDT by multiplying the OKX BTC/USDT index.
D. If not all exchanges are offering valid data, then data taken from each exchange will be weighted as follows.
When data from 3 or more exchanges are available, they will be weighted equally. If an exchange's price deviates more than 3% from the median price of all exchanges, that exchange's price will be taken at 97% or 103% of the median, depending on whether it's too high or too low.
When data from 2 exchanges are available, they will be weighted equally.
When data from only 1 exchange is available, it will be taken as the spot index price.