Trader bought a one month $150 strike CALL OPTION on stock XYZ that is trading for $150. He paid $500 for the contract. After two days, the stock's price is $160 but the trader sees that his contract value is less than $500. Let us say it is $485.
What caused the contract value to drop from $500 to $485 even though the underlying stock price went higher from $150 to $160? My understanding is that Time Decay has not happened so the Option Value should not go down $15 for the contract.