Amazon's (NASDAQ:AMZN) sixth annual members-only event -- Prime Day 2021 -- will officially take place on June 21 and 22, the company announced in a press release on Wednesday, "kicking off with two days of epic deals and the best savings Prime has to offer." Prime Day has become the company's biggest shopping event of the year and has historically surpassed its combined sales from Black Friday and Cyber Monday combined. Customers who aren't Prime members are encouraged to sign up for a 30-day free trial.

The company said it's investing more than "$100 million to help small business sellers succeed." As a result, members will get a $10 Prime Day credit when they spend $10 on select small businesses from June 7 to June 20. Amazon also said that thousands of early deals start today.

While the company doesn't release specific sales figures, Amazon noted that Prime Day 2020 "marked the two biggest days ever for small and medium businesses on Amazon's stores worldwide." Sales during last year's 48-hour event hit roughly $10.4 billion, according to estimates released by Digital Commerce 360, which represents a 45% increase compared to the 2019 event.

Prime Day first debuted in 2015 as a way to celebrate Amazon's 20th anniversary. The online retailer offers members of its Prime loyalty program "Deals of the Day" and "Lightning Deals," which feature a wide range of deeply discounted products and last until inventory runs out. The event originally was one day and billed as "Black Friday in July."

Each subsequent event has been bigger than the last, with the fourth annual event running for 36 hours; last year's Prime Day sale lasted a full 48 hours. It also expanded beyond Amazon's e-commerce site for the first time and included special deals at Whole Foods and other Amazon-owned retailers.

The sale, which has historically been held in mid-July, was delayed until early October last year as a result of the pandemic.

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An Amazon logo is pictured. AFP / INA FASSBENDER

This article originally appeared in the Motley Fool.

Danny Vena owns shares of Amazon. The Motley Fool owns shares of and recommends Amazon. The Motley Fool recommends the following options: long January 2022 $1,920 calls on Amazon and short January 2022 $1,940 calls on Amazon. The Motley Fool has a disclosure policy.