Online spending in the US rose 8.5 per cent to US$11.9 billion during Amazon.com Inc.’s two-day Prime Day promotion, according to Adobe Inc., helping boost traffic on competing sites such as Walmart.com and Target.com that held their own sales.

Amazon sold more than 300 million items over two days, more than any previous Prime Day, the company said Thursday. Best-selling items included diapers, beauty products and Apple watches, according to Amazon.

Inflation-weary shoppers largely stocked up on household items. The Adobe estimate measures total online spending across multiple retailers, based on data from transactions involving more then 100 million products.

The spending uptick was at the higher end of expectations, according to Adobe analyst Vivek Pandya. “Consumers have been dealing with a lot of pricing pressures at the pump, with groceries and in travel,” he said. “They’re still willing to spend if they see discounts.”

The average Amazon order during the event was US$55.26, up 16.8 per cent from Prime Day in 2021 which was held in June, according to Numerator, which based its calculation on 58,934 orders from 21,306 households. Two-thirds of shoppers didn’t seek better prices on other websites and did all their shopping on Amazon, according to the retail consulting firm.

Rising costs prevented many brands and merchants from offering steep discounts. But shoppers showed up eager to spend anyway, seeing any discount as a hedge against inflation that rose 9.1 per cent in June, more than expected. Spending on Amazon was expected to reach US$7.76 billion in the US and US$12.5 billion globally over the two-day event, each up about 17 per cent from a year earlier, according to research firm EMarketer Inc., which said inflation would make shoppers hungry for deals.

Amazon launched Prime Day in 2015 to attract new subscribers who pay US$139 a year for shipping discounts, video streaming and other perks. The event helps Amazon lock in shoppers before the holidays and deepen its relationship with existing customers by offering them deals on Amazon gadgets.