Internet sales in the U.S. this holiday season are up 15 percent to $24.6 billion, according to comScore.
So far, consumers have spent about $25 billion online.
ComScore, a digital research firm, said single-day sales exceeded a billion dollars six times so far. One of those days included Cyber Monday, the Monday after Thanksgiving, when sales hit $1.25 billion.
Sales for the week ending Dec. 9 rose 15 percent to $5.9 billion, the Reston, Va., company reported.
"As we enter what will be the heaviest week of the season for online retailers - beginning with 'Green Monday' on Dec. 12 - all signs are now pointing to a strong finish to the season," comScore Chairman Gian Fulgoni said.
Green Monday, traditionally the second Monday of December, was coined by eBay, Inc., to describe the best sales day in December. Although the day has consistently ranked among the top spending days of the season, it is no longer the top online spending day.
"Free Shipping Day," occurs on Friday, Dec. 16, of this year.