Did Prime Day deliver for Amazon investors?

Amazon earnings on deck: What to watch

We know's Prime Day last week was big. Just how big may become clearer in the company's Q2 earnings report Thursday afternoon.

Piper Jaffray analyst Gene Munster predicts the one-day sale celebrating Amazon's 20th anniversary added 2 percent to unit growth for the current quarter (Q3). Michael Pachter of Wedbush Securities estimates that $1.2 billion in revenue came in the door on July 15.

Despite becoming the butt of Twitter jokes due to products quickly selling out and an abundance of Tupperware deals, Amazon said customers ordered 34.4 million items, more than its biggest ever Black Friday.

Investors will be looking at Amazon's third-quarter forecast to see the impact.


Kindle readers, diapers and limited edition releases of "Breaking Bad" all flew off the virtual shelves. Because the deals were only open to $99-per-year Prime subscribers, the campaign was as much about bringing in new members as it was same-day sales.

"We continue to view Prime as one of the most important drivers of growth for Amazon and believe that this campaign will only strengthen its perceived value among consumers," Munster wrote in a July 16 report. He has the equivalent of a buy rating on the stock and a price target of $520, 6.5 percent above Wednesday's closing price or $488.27

Read More 3 things to watch from Amazon earnings

In the Seattle-based company's second-quarter earnings report, analysts expect to see 16 percent revenue growth to $22.4 billion, according to a Thomson Reuters survey. Analysts expect 16 percent growth in the third quarter as well to $23.9 billion, though Amazon typically provides a fairly wide range in its forecast.

One thing hasn't changed: CEO Jeff Bezos is still shunning the virtues of profitability. The company is expected to lose 13 cents a share, following a loss of 27 cents a year earlier.

Prime Day to become an annual event

And investors continue buying into the dream of future earnings. The stock has climbed 35 percent in the past year, giving Amazon a market value of $227 billion, fifth-biggest among U.S. technology companies.

JMP Securities analyst Ronald Josey upgraded Amazon shares on Wednesday to "market perform," in part because of the company's investment in Prime and the "hundreds of thousands" of new users he predicts joined on Prime Day.

Read MoreSame-day delivery boosts Prime membership

Prime membership includes free two-day shipping as well as unlimited streaming of movies and TV shows.

Josey, who has a $575 price target, estimates there are now 40 million to 50 million Prime members, spending on average double the amount that nonprime users spend.

Amazon's growing cloud

Analysts are also focused on Amazon's cloud-computing business, Amazon Web Services, which the company started reporting as a separate unit in the first quarter.

Emerging start-ups, Netflix streaming and even the CIA count on Amazon's vast global network of on-demand servers and storage.

AWS revenue is projected to grow 50 percent to $1.51 billion in the second quarter, according to FactSet, accounting for 6.7 percent of sales.

As a true technology platform, AWS is actually profitable, with a 17 percent operating margin in the first quarter, compared with an overall margin of 3.1 percent.

Read MoreMicrosoft gathers ammo for cloud war with Amazon

"AWS has become a significant part of the business, and new features lead us to expect dramatic profit growth in the coming years," Wedbush's Pachter wrote in a July 19 report.

Pachter upgraded the shares to "outperform" and raised his price target to $575 from $435, citing AWS growth and "greater sales traction from Prime Day than we expected."

Clarification: This story was updated to say that Prime Day numbers will likely show up in the Q3 forecast.