What happened

Shares of programmatic ad platform The Trade Desk (TTD -1.52%) took a hit on Thursday. As of 11:30 a.m. EDT, the stock was down more than 18%.

The stock's decline follows The Trade Desk's first-quarter results. Though the quarter's top- and bottom-line results crushed estimates, high expectations meant in-line second-quarter revenue guidance spooked some investors.

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Image source: Getty Images.

So what

The Trade Desk's first-quarter revenue increased 41% year over year to $121 million. Analysts, on average, were expecting revenue of $117 million. Non-GAAP earnings per share increased from $0.34 in the first quarter of 2018 to $0.49, also easily beating a consensus analyst forecast for $0.25.

"In Q1, we continued to develop closer relationships with the biggest brands in the world," said The Trade Desk CEO Jeff Green in the company's first-quarter earnings release. "Over half of the companies in the S&P 500 have run campaigns on our platform. We are executing well."

The company's guidance for second-quarter revenue of $154 million, however, was in line with what analysts were looking for.

The Trade Desk stock has been surging this year, putting immense pressure on Thursday's earnings report. Even after today's sell-off, shares are up 55% year to date and more than 250% over the past year.

Now what

With a strong first quarter behind it, The Trade Desk lifted its outlook for the full year. Management said it expects full-year revenue of at least $645 million, up from previous guidance for revenue of $637 million or greater. In addition, The Trade Desk guided for adjusted EBITDA for 2019 of $188.5 million, up from guidance for $182 million.