The explanation to the backwardation and contango of Shanghai spot price

The backwardation and contango of SHMET copper price is the difference between the copper spot price and SHFE copper ask price of the same month; that of the first price is the difference between the spot price and SHFE 10:15 ask price of the same month. And that of the last price is the difference between the spot price and SHFE 11:30 ask price.

The backwardation and contango of SHMET aluminum price is done in the same manner.

However the backwardation and contango of SHMET zinc price is the difference between the zinc spot price and SHFE three-month zinc ask price; that of the first price is the difference between the spot price and SHFE 10:15 three-month ask price. And that of the last price is the difference between the spot price and SHFE 11:30 three-month ask price.