"Consumer confidence is high and retailers have been aggressive with broad sitewide or category-wide discounts, which have also helped encourage shoppers to open their wallets."
Sales growth from Thanksgiving through Sunday, she added, topped Forrester's average holiday growth estimate of 12 per cent. The firm is now forecasting a 16 per cent uptick for the holiday weekend.
Many brick-and-mortar retailers highlighted their Internet sales. Department store chain Kohl's said its website had a "record-breaking" Thanksgiving, with nearly 16 million online visits that day, while rival JC Penney said online traffic had increased "double digits" the week of Thanksgiving, as consumers used mobile devices to buy diamond jewelry, furniture and refrigerators.
"Traffic peaked on Thanksgiving Day, with the site receiving more visits than any other day this year," JC Penney said in a Friday blog post.
Amazon.com, the country's largest online retailer, has yet to report holiday shopping results, except to say said it sold more than 200,000 toys in the first five hours of Black Friday, and that its best-selling items include Amazon Echo devices, Instant Pot pressure cookers and 23 and Me DNA tests.
Earlier this year, the company said its annual Prime Day in July had surpassed Cyber Monday and Black Friday to become the largest sales day in Amazon history.
Amazon.com now accounts for about 43 per cent of all online sales, according to estimates from research firm eMarketer. (Jeffrey P. Bezos, the founder and chief executive of Amazon, also owns The Washington Post.)
It hasn't been smooth-sailing for all retailers. Macy's said it had "system issues" on Friday that led to problems processing credit cards and gift cards in stores around the country.
Many shoppers took to social media to voice their frustrations, creating a new set of challenges for the department store company, which has reported 11 consecutive quarters of sales declines.
"The delays we experienced were due to a capacity-related issue that caused some transactions to take longer to process," the company said in an email on Saturday. "We do not anticipate any additional delays."
But as online spending hits record highs, fewer Americans are heading to the store. In-store visits on Thanksgiving and Black Friday dropped 1.6 per cent from a year ago, according to retail analytics firm ShopperTrak.
Overall, holiday spending is expected to increase as much as 4 per cent this year, to US$680b ($983b), according to the National Retail Federation, which will release final results Tuesday afternoon.
But analysts say retailers - which rely heavily on the holiday shopping season to boost annual sales - can't rest easy just yet.
"The bad news: Retailers also face a huge challenge now in shipping all these orders to customers in a timely fashion," Mulpuru-Kodali said. "The holidays are a time for joy but irritated customers who don't receive their packages on time are not so joyous."
