NEW YORK — ShopperTrak, which analyzes customer traffic at US stores, cut its holiday sales forecast because shopping has limped along since the Thanksgiving weekend buying frenzy.
ShopperTrak, of Chicago, said Wednesday that it now expects holiday sales to be up 2.5 percent, down from its 3.3 percent projection issued in September.
It cited Hurricane Sandy and ‘‘heavily discounted merchandise’’ for the reduced forecast, which compares with a 3.7 percent increase a year ago.
ShopperTrak still believes that foot traffic will be up 2.8 percent from a year ago, the first increase in visits for the holiday season since 2008.
‘‘We were hoping that this past Saturday would be the kickoff to good things to come,’’ said Bill Martin, the cofounder of ShopperTrak. ‘‘But it feels like the steam is out of the holiday since Black Friday.’’
Martin also believes the Newtown, Conn., school shootings had an effect in tempering the mood of shoppers over the weekend. ‘‘Christmas may be more about being with the family than putting gifts under the tree,’’ he said.
For the week ended on Saturday, foot traffic was up 15.1 percent, and retail sales rose 16.4 percent over the previous week. But compared with the year-earlier period, foot traffic was down 4.4 percent and sales declined 4.3 percent.
The November-December period accounts for as much as 40 percent of retailers’ annual sales. ShopperTrak monitors data from 40,000 retailers.