Given that Amazon has officially extended Prime Day to a two-day event this year, it won’t be any surprise when the retailer inevitably announces it has set a new sales record. There are decent odds it would do so even if Prime Day 2019 was a single day event, given consumer excitement surrounding the bargain-heavy shopping festival.
But there’s a lot more to be told once you scratch beyond the initial sales numbers.
Last year, Amazon sold over 100 million products on Prime Day. Even when adjusted for last year’s 36-hour sales period, sales surpassed Cyber Monday, Black Friday and 2017’s Prime Day (which, itself, improved upon the 2016 event by 60%).
The company did not give sales totals in dollars last year and likely won’t this year. However, IgnitionOne, a marketing technology and services firm, estimates Amazon will generate sales of $6.1 billion on Prime Day 2019, which it says is a $2 billion improvement over last year.
One reason Amazon might not crow about those numbers is that impulse purchases often result in returns. Adobe Analytics says last year saw a 30% increase in returns for items purchased over Prime Day.
And while Prime Day might have started as a vehicle to boost subscriptions to Amazon’s multi-hyphenate membership service, it has since become a day that benefits the company’s competitors as well.
Target, Walmart, Ebay and more are all offering sales of their own that will run concurrent with Prime Day. And they’re getting better at luring online shoppers to their sites. Adobe predicts a 79% revenue lift this year for top retailers, a notable improvement on last year’s 60% lift.
“Big e-commerce competitors have become better at reaping the benefits of this artificial holiday,” said Taylor Schreiner, principal analyst at Adobe Digital Insights (ADI). “After all, they’ve now had almost five years of practice in converting Prime Day traffic.”
More must-read stories from Fortune:
—8 ways to track the best Amazon Prime Day deals
—Amazon Prime subscription growth slows ahead of Prime Day 2019
—Fortune’s 2019 40 Under 40
—How automation is cutting into workers’ share of economic output
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