Amazon.com (NASDAQ:AMZN) has a long history of mysteriously touting accomplishments but without providing more context. As frustrating as that can be, at least investors know that the company is heading in the right direction. Amazon this week announced that its core e-commerce segment in the U.S. broke numerous new records over the holiday shopping season -- without elaborating what those records are.

Separately, Mastercard also released a report around holiday shopping that added fuel to Amazon's bullish fire.

Amazon worker loading orders on a conveyor belt

Image source: Amazon.

What Amazon said

There were several new records set over the holiday shopping season on the tech giant's e-commerce platform. Key among them was third-party merchant sales, which saw unit sales jumping double digits and topping a billion items sold, according to Amazon. These merchants are predominantly small- and medium-sized businesses, and CEO Jeff Bezos' annual shareholder letter this year noted that third-party sellers comprised a whopping 58% of physical gross merchandise sales in 2018.

"This holiday season has been better than ever thanks to our customers and employees all around the world," Bezos said in a statement. "On behalf of all Amazonians, we wish everyone the happiest of holidays and a fantastic 2020."

Amazon added that this year saw the highest number of Prime free trials, including one week when over 5 million customers signed up for Amazon's popular membership program. Amazon hit 100 million Prime members globally in early 2018 and has not provided any official updates since (there are plenty of third-party estimates, though).

Echo Show 5 on a nightstand

Image source: Amazon.

Amazon's devices like Echo speakers and Fire TV Sticks also enjoyed record sales, with the company selling "tens of millions" of gadgets. Compared to 2018, customers bought "millions more" Amazon devices, with the Echo Dot, Fire TV Stick, and Echo Show 5 being among the most popular products. That should help Amazon maintain its dominance in the smart speaker market, where it grabbed 37% market share in the third quarter, according to Canalys. Engagement remains strong, too, with users interacting with Alexa "at record levels."

What Mastercard said

The credit card payment network released its SpendingPulse report, which showed that overall U.S. retail sales grew 3.4% over the holiday shopping season, which Mastercard defines as Nov. 1 through Dec. 24. Importantly for Amazon, e-commerce sales growth is accelerating. E-commerce sales jumped 18.8% this season, up from the 18.4% growth in 2018, according to the report.

"E-commerce sales hit a record high this year with more people doing their holiday shopping online," senior advisor for Mastercard and former Saks CEO Steve Sadove said in a statement. "Due to a later than usual Thanksgiving holiday, we saw retailers offering omnichannel sales earlier in the season, meeting consumers' demand for the best deals across all channels and devices."

The strongest category for online sales was apparel, which saw e-commerce sales soar 17%, which was better than expected. Amazon has been aggressively expanding into clothing with a broad stable of private-label brands, although its efforts have hit speedbumps compared to physical retailers that similarly offer private-label brand apparel.

Consumers continue to shift toward e-commerce, a decades-long trend that shows no signs of slowing down. This year, e-commerce represented 14.6% of total retail, suggesting that there's still more upside for e-commerce.