The Trade Desk Inc. shares tumbled as much as 30% in after-hours trading on Wednesday after the advertising-technology firm issued quarterly results that, while ahead of Wall Street estimates, failed to match investors’ heightened expectations. For the second quarter ended June 30, the company reported earnings of $0.41 a share, in line with analyst forecasts, on revenue of $694 million, topping the $685 million consensus. Management said it expects third-quarter revenue of more than $717 million, slightly above the roughly $714 million projected by analysts, and reiterated its focus on data-driven ad buying across the open internet’s “big five” content pillars. The market reaction came despite the modest beat and guidance lift and coincided with the announcement of a new chief financial officer. The stock, which joined the S&P 500 earlier this year and trades at an estimated 40 times forward EBITDA, has been sensitive to even minor disappointments as investors weigh lofty valuations against the company’s growth trajectory.