By Quality Stock Arts @ Shutterstock.com

Matt Day, andย Spencer Soper of Bloomberg write (abridged):

US shoppers spent $12.7 billion online duringย Amazon.com Inc.โ€™s 48-hour Prime Day, up 6.1% from a year ago but short of estimates for 9.5% growth, according to Adobe Inc.

An increasing share of customers used โ€œbuy now, pay laterโ€ services, Adobe said, indicating shoppers are concerned about the economy.

โ€œFor months, consumers have felt the effects of persistent inflation and an uncertain economic environment, and it has pushed shoppers to embrace more flexible ways to manage their spending around the Prime Day event,โ€ said Vivek Pandya, an analyst with the technology company. โ€œThe revenue growth attributed to buy now, pay later is a preview of what we can expect in the months ahead, especially as we near the holiday shopping season.โ€

Adobe measures total spending on US online shopping sites during the Prime Day period because a host of retailers, including Walmart Inc. and Target Corp., draft off Amazonโ€™s marquee summer sale, offering their own discounts and boosting overall e-commerce sales at a time of year when shoppers typically pull back.

Amazon shares rose almost 3% in New York, part of a broader rally.

Numerator, which tracked purchases by more than 34,000 unique buyers on Amazon, said the average order size during the event was $54.05, up about 3% from a year earlier. More than half of Prime Day shoppers surveyed by the data provider say they compared Amazonโ€™s prices with those at other retailers before making their purchases. Amazon Chief Executive Officerย Andy Jassyย said in an interview with CNBC last week that price-conscious shoppers were โ€œtrading down whenever they canโ€ given the uncertain economy.

โ€œIn an event typically dominated by electronics, we instead saw many shoppers stocking up on everyday essentials like pet food or pantry staples,โ€ Numerator analyst Amanda Schoenbauer said in a statement. โ€œIt seems many used the event to save on their standard purchases or held off on buying larger ticket items until the sale came around.โ€

Insider Intelligence expected shoppers worldwide to spend an estimated $12.9 billion on Amazon during the event, up about 11% from last year.

Amazon doesnโ€™t break out the financial metrics of its biggest sale, instead releasing mostly anecdotal information about top sellers. The company on Thursday said the first day of the sale was the biggest in its history and that shoppers purchased more than 375 million items over two days.