A survey showed that online retail sales were jumping for "Cyber Monday," the key Web shopping day following the US Thanksgiving holiday weekend.
IBM said its cloud-based digital analytics platform showed sales up 24.1 percent from last year as of 1700 GMT.
"All signs point to Cyber Monday being a banner year," IBM said on its Digital Analytics Benchmark blog.
"With sales up 24.1 percent over 2011, the multiscreen shopper is out in full force this year. Mobile continues its dominance, with the number of consumers using a mobile device to visit a retailer's site reaching 22.4 percent."
IBM said the number of consumers using their mobile device to make a purchase was 12 percent.
"The iPhone continues to drive more retail shopping than any other device with traffic reaching 8.7 percent versus 7.2 percent and 6.3 percent for iPad and Android respectively," said IBM.
The company based its data on "the industry's only cloud-based Web analytics platform that tracks more than a million e-commerce transactions a day."
The hot Monday sales came after surveys showed heavy online spending for Black Friday, the day after Thanksgiving.
Online shoppers spent a record of $1.042 billion on Friday, surpassing last year's Black Friday haul by 26 percent, according to the consulting firm comScore.
A total of 57.3 million Americans visited online retail sites on Black Friday, representing an increase of 18 percent versus a year ago, the firm said.