4. Index price

To ensure that the spot index price reasonably reflects the fair spot market price of each currency, we will select the currency pairs of 3 mainstream exchanges for each contract currency as the index weight component, and design exception handling logic. If some exchanges If the market deviates significantly or an exchange is interrupted, Dcoin will automatically remove the exchange data from the index, that is, it will no longer participate in index calculations until its trading returns to normal, ensuring that the index fluctuations are normal when the price of a single exchange deviates significantly, within range.

1.Weight of Index list:

Index	Exchange	Trading pair	Weight
BTC/USDT	Bitstamp	BTC/USDT	20%
	OKCoin	BTC/USDT	20%
	Gemini	BTC/USDT	20%
	Kraken	BTC/USDT	20%
	Coinbase	BTC/USDT	20%

Spot index price calculation logic
a. Obtain the latest transaction price and volume of all index component exchange currency pairs of the currency in real time;

b. System maintenance or exchanges that have not updated the latest transaction price and volume for 15 minutes will be invalidated and will not participate in the calculation this time;

c. The valuation currency is the currency pair of BTC, which is multiplied by the BTC price in Dcoin  and converted into US dollar price;

d. Determine the current remaining valid exchange data:
When there are 3 effective exchanges, the effective exchanges are weighted with equal weights (if the price of a certain exchange deviates by more than 3% from the median price of all exchanges, the exchange price will be based on the median * 0.97 or the median Number of digits * 1.03 calculation);
When there are two effective exchange data, the effective exchange data is weighted with equal weight;
When there is one effective exchange data, the price of the remaining one effective exchange is directly used as the index price.