What happened

Shares of programmatic digital ad-buying platform operator The Trade Desk (TTD 0.62%) popped 15.6% in July, according to data from S&P Global Market Intelligence.

For context, the S&P 500, including dividends, edged up 1.4% last month. 

Hand holding a TV remote control pointing at a digital TV with many images/channels shown on menu.

Image source: Getty Images.

So what

We can attribute The Trade Desk stock's strong performance last month in part to a continuation of the positive momentum it's enjoyed for some time, thanks to the company's robust growth. But the biggest catalyst came on July 26, when shares surged 9.1% following Amazon.com's (AMZN 2.08%) announcement that its Amazon Publisher Services (APS) platform, a sell-side ad platform, is partnering with The Trade Desk and another demand-side platform (DSP), Dataxu TouchPoint. 

TTD Chart

Data by YCharts.

As my colleague Daniel Sparks wrote at the time, "The partnership gives ad agencies and brands using the two DSPs access to ad inventory available through APS, which consists of ads on ad-supported content on Amazon's Fire TV marketplace. On the flip side, this means publishers using APS now get access to marketers using The Trade Desk's platform."

So far in 2019, The Trade Desk stock is up a whopping 125%, versus the broader market's 18.3% return. 

TTD Chart

Data by YCharts.

Now what

Investors don't have long to wait for material news. The Trade Desk is slated to release its second-quarter results on Thursday, Aug. 8, after the market close. Wall Street is looking for adjusted earnings of $0.69 per share on revenue of $155.6 million, representing year-over-year growth of 15% and 38.6%, respectively.

Given the stock's torrid performance in 2019 and pricey valuation -- shares are trading at a forward price-to-earnings ratio of 72 -- investors surely have high expectations for the second quarter's results. So The Trade Desk needs to deliver or the market will likely be unforgiving.