Amazon (AMZN.US) had a booming start to its Prime Day, with daily sales far surpassing 2023's.

A new report from Adobe Analytics released on Wednesday shows that U.S. retailers' online sales on the first day of Amazon's Prime Day, the company's annual shopping event for its members, reached a whopping $7.2 billion, compared with the $12.7 billion in online sales during the two-day Prime Day event in 2023. Notably, major retailers including Walmart and Target had rolled out discounts and promotions before July, offering steep discounts to compete with Amazon's Prime Day event.

Adobe Analytics' data showed that Amazon took some market share from other large retailers this month, as customers can enjoy large discounts on a wide range of products and order items that can be delivered the same day or within one day.

Amazon's Prime Day runs from July 16 to 17 Eastern time.

Adobe Analytics data showed that U.S. back-to-school spending also saw an unexpected surge, with Tuesday's daily sales up about 210% compared with the daily average sales in June 2024.

Adobe Analytics said that online sales totaled $11.7 billion on Tuesday alone, up 11.7% from the same day in 2023. The data company said that the total online spending by global shoppers participating in the Prime Day event reached about $12.7 billion in 2023, which was close to the historical peak.

Adobe Analytics said that shoppers would start large purchases on Wednesday, with the company expecting discounts of about 23% on electronics, 20% on clothing and 15% on toys. The data company's data is based on direct-to-consumer (DTC) transactions, which are based on the number of visits to U.S. retail websites that exceed 10 billion.