when exercising the wild card option the seller of the treasury futures contract would wait to see whether the spot price declines below the invoice price during after hours trading if it does then the seller could exercise their wild card option and make their delivery based on the low spot price decreasing the overall cost of their short position 
example of a wild card optiontreasury bond futures contracts are among the most actively traded investment securities in the world to illustrate how a wild card option works in practice consider the case of abc capital a hypothetical investment firm that has taken a short position in the treasury market by selling treasury bond futures contracts as the seller of the treasury bonds abc capital is obligated to deliver a specified quantity of treasury bonds to the buyer at a predetermined time once the settlement date is reached however abc capital can opt to use the wild card option embedded in its futures contract on the settlement date abc capital can therefore wait for up to 6 hours following the end of the trading day before announcing its intention to deliver the bonds during those 6 hours the market price of bonds during after hours trading might sink giving abc capital the chance to purchase bonds at a more favorable price before rendering them to the buyer this in turn would lower the cost of abc capital s short position thereby increasing their profit or reducing their loss 