This is div day, but the x-date was a couple of months ago. The effect of the div is already factored into the price. This big down at opening is odd.....means somebody is playing with the stock. i can't help but wonder if they sell BTI and buy PM.
Also; EX Div simply means that any share holder of record will get the div from that day forward, but it is not the day that affects the stock price, the stock price is affected on the pay date, and normally goes down equal to the payout, any other fluction would be due to the market on that day. hope this helps!