NEW YORK — Barnes & Noble, which announced a round of layoffs this week, is pointing to new staffing rules that will allow stores to increase or decrease the number of people on the clock depending on need.

The nation’s largest book chain said Tuesday in a filing with the Securities and Exchange Commission that the change will lead to annual cost saving of $40 million.

The company insists that the staff cuts will not affect customer service.

Barnes & Noble said Monday that it was trimming its work force after a weak holiday shopping season. It did not say how many people were being let go.

The New York bookseller, which has struggled to compete with Amazon, said last month that sales at established locations slid 6.4 percent during the holidays.