The short holiday season could cost retailers $1.5 billion, a new survey says. Above, a shopper looks at a price tag in Miami. (Joe Raedle/Getty Images)

There are six fewer days between Thanksgiving and Christmas this year, the shortest holiday season in more than a decade.

The calendar could cost retailers $1.5 billion in lost sales, according to a report released Tuesday, another signal of the high stakes for stores.

That is one reason “holiday creep” started earlier this year, analysts said. Macy’s, J.C. Penney and other department stores said they would open on Thanksgiving for the first time. Wal-Mart, Target and other big-box retailers have begun offering discounts usually reserved for Black Friday.

“Promotional activity will be bigger, earlier and more noisy,” said Tamara Gaffney, principal analyst at Adobe Digital Index, which released the report.

The race to attract consumer dollars matters more than ever as retailers battle the effects of the government shutdown and mediocre jobs reports. Consumer confidence took a hit last month because of the shutdown. New estimates of the country’s growth rate and October’s jobs report, due out this week, are expected to be disappointing.

Despite these factors, holiday sales are projected to increase by nearly 4 percent this year, and online sales by 15 percent, according to the National Retail Federation.

Although consumers are frustrated with the economy, that has not translated into a reduction in spending, the retail group said last month.

For retailers, the holiday season is the most critical shopping period of the year, representing between 20 and 40 percent of annual sales, according to the retail group. Consumer spending accounts for more than two-thirds of demand in the U.S. economy.