Amazon's 2nd Prime Day orders breezed past first-year totals

The e-commerce powerhouse launched the event last July to promote its $99 annual Prime loyalty program, which offers free two-day shipping and other perks.

The loyalty program is a key platform for Amazon because Prime members shop more frequently and spend more money.

The Fire TV stick was the best-selling Amazon device and it was the biggest sales day for Amazon's smart speaker the Echo.

PiperJaffray analyst Gene Munster said Amazon's results beat his expectations for 37 percent growth, and the results solidify Prime Day as an annual holiday sales day.