RESTON: US e-commerce sales have risen to an all-time high, with overall online retail spending up 15% from 2010 over the festive period.

Researchers at comScore said that spend hit $30.9bn over November 1st-December 16th 2011, an increase from the $26.9bn recorded over the equivalent period last year.

Meanwhile, spending for Cyber Monday on November 28th, during which many e-commerce vendors launched deep discounts, was up 22% year-on-year to $1.3bn.

Cyber Monday, which falls each year on the Monday following Thanksgiving and the Black Friday sales, again proved to be the biggest-spending day of the year.

But other heavily-marketed days also encouraged spikes in online consumer spending.

Green Monday, or the second Monday in December, attracted an overall US spend of $1.1bn this year, while Free Shipping Day (December 16th), on which many retailers dropped their postage charges, recorded just over $1bn.

Spending on these days beat their 2010 equivalents by 19% and 14% respectively.

Participation in Free Shipping Day was found by comScore to have increased from last year. During the week ending December 18th, 56% of overall online retail transactions did not include postage charges, up 3.8pp from 2010.

But the report also suggested that many retailers were front-loading their festive promotions.

Despite the marketing surrounding Free Shipping Day, the proportion of transactions bundled with free shipping was found to have actually peaked at 64% over the week ending November 27th.

Gian Fulgoni, comScore chairman, added: "While next week may see another strong day or two at the beginning of the week, it's clear that we have now reached the crescendo for this season and that spending will begin to slow as we get closer to Christmas, leaving Cyber Monday as the top ranked shopping day for the second year in a row."

Data sourced from comScore; additional content by Warc staff