There was little doubt that's (NASDAQ:AMZN) Prime Day this year had the potential to outdo its predecessors. What began as a 20th anniversary celebration and a thank-you to Prime members has gotten bigger every year since, stretching to 48 hours in 2019, up from 36 hours in 2018, and 30 hours the year before. As in years past, Amazon touted an event that would be bigger than ever, promising a "two-day parade of epic deals." 

The fifth annual event wrapped up Tuesday, and Amazon is reporting that its sales surpassed sales of both Black Friday and Cyber Monday combined. Let's take a look at the highlights and see if Prime Day delivered the goods.

An Amazon fulfillment center employee picking items out of a bin for shipping

Image source: Amazon.

Next verse same as the first

Amazon said Prime Day was once again "the largest shopping event in Amazon history," according to its press release. The company served up more than 1 million deals for Prime members to choose from, and a record number of shoppers purchased more than 175 million items during the two-day event. Members in 18 countries shopped – double the number of countries participating in the first Prime Day.

Even better for Amazon, the company revealed that it was the biggest event ever for Amazon-branded devices. The top sellers worldwide were Echo Dot, Fire TV Stick with Alexa Voice Remote, and Fire TV Stick 4K with Alexa Voice Remote.

The company also said it was "the biggest event ever" for a host of Alexa devices with screens, such as the Echo Show and Echo Show 5. This was also the best Prime Day ever for Fire tablets, with the Fire 7 tablet as the top seller. The company sold a record number of Kindle devices, and customers purchased two times as many Fire TV Edition Smart TVs than last year's record-setting Prime Day. Amazon also sold six times as many eero home Wi-Fi devices than during any previous sales event.

Amazon said it sold "hundreds of thousands" of Amazon devices for kids, including the Echo Dot Kids Edition, Fire 7 Kids Edition tablet, and Fire HD 8 Kids Edition tablet.

Excluding Amazon devices, the best-selling products in the U.S. were the LifeStraw Personal Water Filter, Instant Pot DUO60, and 23andMe Health + Ancestry kits.

Prime Day 2019 was also a record-breaking success for independent third-party sellers -- mostly small and medium-sized businesses. Globally, these businesses far exceeded $2 billion in sales.

Growing the rolls of Prime memberships?

Another highlight of the event: Amazon said it welcomed more new Prime members on July 15 than any other day in the company's history, and nearly as many on July 16, "making these the two biggest days ever for member signups."

While members signed up in record numbers, there is some question about how many will actually stay beyond the 30-day free trial, or even beyond the Prime Day sale itself. Internet searches for "canceling Amazon Prime" were 18 times higher on Monday -- the first day of the Prime sale -- than they were the day before, according to data compiled by search retargeting service Captify. 

"If Amazon is hoping to use Prime Day as a way to sign up and retain new Prime members, they might need to rethink their retention plan," said Captify. "According to search, consumers are signing up for Prime, getting their deals and then canceling membership shortly after."

Amazon has a vested interest in trial members sticking around, as Prime shoppers typically spend $1,400 per year on average, compared to $600 for non-Prime customers, according to data provided by Consumer Intelligence Research Partners. 

The Amazon Prime Day logo, surrounded by products and celebratory balloons, etc.

Image source: Amazon.

How big was it really?

Amazon has been notoriously tight-lipped about Prime Day numbers in prior years, and this year was no different. While the company provides a wealth of other less-meaningful metrics, it has steadfastly refused to release any exact data regarding sales. But that hasn't stopped outside sources from doing their best to calculate estimates, though the numbers vary wildly.

J.P. Morgan analyst Doug Anmuth said Prime Day sales could top $5 billion this year for Amazon, which would represent a 56% increase from the $3.2 billion he estimates the company grossed last year. 

Some guesses are even more robust. The online shopping leader is expected to generate about $5.8 billion in global sales during its Prime shopping event, up about 49% year over year, according to a report by Coresight Research.  

Whatever the real final tally, we already know that Prime Day was Amazon's biggest shopping event ever.

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