think about that and think about how big facebook has grown. joining me now cnbc s julia bore steen. back us through this. when the cambridge analytica came out, we did see facebook take a tumble. then the stock went up 43%. when you saw mark zuckerberg testify on the hig, it was pretty clear he s not getting regulated any time soon. well, here are the factors that really september the stock down last night. first the company missed expectations on revenue and user growth. earnings beat expectations but the revenue earnings and number were just a hair lighter than expected. what really september the stock tumbling was during the earnings call when the cfo warned that revenue growth was going to continue to decelerate pretty significantly in both the third and fourth quarter of the year.