Consumers spent $2.03 billion between Dec. 13 and Dec. 17. This represents an increase of 49% compared to the corresponding days last year, according to comScore Network.

The Reston, Virg.-based company, which studies consumer behavior and attitudes, has been tracking online spending on weekly basis during the holiday season. It says the strong performance is likely the result of three key factors:

* Thanksgiving fell two days earlier than in 2003, helping to extend the peak spending period.

* E-mail campaigns on the part of many retailers reminding consumers of shipping deadlines, and guaranteeing on-time arrival for products purchased last week.

* An increased number of retailers allow shoppers to buy online and pick up in-store, which removes lead times associated with shipping and allows consumers to buy online later in the holiday season.

As a result of last week’s strong spending levels, online sales are now tracking at 26% over last year’s levels, comScore says. Consumers have spent $13.1 billion dollars online between Nov. 1 and Dec. 17, compared to $10.4 billion during the corresponding days last year.

“Every day between Monday and Thursday of last week, consumers spent more than $400 million online,” said Dan Hess, senior vice president of comScore Networks. “Shoppers responded to retailers’ call to action, delivered through email shipping time alerts and reminders of the ability to buy online and pick up products in-store.”

JCK