(NASDAQ:AMZN) recently passed an important milestone, becoming just the second U.S. company in history to top a $1 trillion market cap. Part of what drove the company to those dizzying heights was the impressive results Amazon has produced so far this year. The company grew revenue an impressive 41% year over year in the first half of 2018, but Amazon Web Services (AWS) is doing even better, up 48% compared to the first six months of last year. It's also improved operating margins across each of its business segments, while quietly growing another business (B2B commerce) to $10 billion per year.

All signs point to another strong performance when Amazon reports the financial results of its third quarter after the market close on Thursday, Oct. 25, but let's look at Amazon's most recent results and see what the company will need to do to continue its upward momentum.

A bird's eye view of an Amazon warehouse sporting solar panels on the roof.

Image source: Amazon.

Outlook cloudy -- and that's a good thing!

For the second quarter, Amazon reported revenue of $52.9 billion, up 39% year over year. Operating income of $2.98 billion came in at nearly double the company's forecast for $1.5 billion. Profitability soared, with net income of $2.5 billion producing earnings per share of $5.07, up 1,168% compared to the prior-year quarter. 

Much of this earnings outperformance was a function of the company's operating margin, which improved across the board on a trailing-12-month basis. AWS continues to draw most of the headlines, with revenue of $6.1 billion this quarter, an increase of 49% year over year, and growing to 11.5% of Amazon's total second-quarter sales. With juicy operating margins approaching 27%, this cash cow is helping finance the company's international expansion. Watch for continued improvement in this metric over time.

Amazon revealed that its recent focus on its advertising business is bearing fruit, exceeding $2 billion in each of the past two quarters, while its business-to-business (B2B) operations are expected to top $10 billion annually.

The big wild card in this quarter will the results of Amazon Prime Day, its customer loyalty sale that was held for 36 hours beginning on July 16. The company typically keeps the financial results of its annual event close to the vest, but some estimates placed Amazon's sales at $2.4 billion last year, and projections are upwards of $3.4 billion this time around. When the company produced a blowout third quarter last year, CFO Brian Olsavsky chalked it up to Prime Day, saying, "I wouldn't point to anything other than the Prime Day pickup ... it was stronger than probably I anticipated."

An computer-generated image of an Amazon box opening with a multitude of items coming out and a sign the says, "Prime Day. Starts July 16, 3PM Eastern Time."

Image source: Amazon.

Another quarter of impressive growth?

For the third quarter, Amazon is anticipating revenue between $54 billion and $57.5 billion, which would represent year-over-year growth in a range of 23% to 31%, which includes an unfavorable impact of 30 basis points from currency fluctuations. Operating income is expected to come in between $1.4 billion and $2.4 billion, achieving growth of between 303% and 592% compared to the prior-year quarter.

While we won't be beholden to Wall Street prophecies, they can be a tool in providing context. Analysts' consensus estimates are calling for revenue of $57.08 billion -- near the high end of Amazon's estimate -- and earnings per share of $3.10, an increase of 496% compared to the prior-year quarter. 

There are no guarantees that Amazon will crush estimates, as it has done so often. If the company sees an opportunity to invest for long-term growth -- even at the expense of quarterly results -- it won't hesitate to do so. You need look no further than the 2017 second quarter for a perfect example of that.

That said, with another Prime Day under its belt, this could be another blowout quarter for investors.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.