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In the option table for SPY there is a column called 'Price' and a column called 'Bid' and a column called 'Ask'.
If I wish to buy a call option, I need to pay a premium. Which column is the premium I would pay? Is it the 'Price'? But isn't the 'Price' supposed to be mid-way between the 'Bid' and 'Ask'? Why wouldn't it be?