Barnes & Noble reported disappointing sales for the nine-week holiday period ended December 30, 2017. Total sales for the period fell 6.4%, to $953 million, compared to the holiday season in 2016. The retailer said that comparable store sales also dropped 6.4%, compared to the prior year, while online sales declined 4.5%.

The weaker than expected holiday results caused B&N to lower its forecast for the full year ending in April. B&N said it now expects comparable store sales to fall in the mid-single digits; previously it expected same store sales to decline in the low single digits.

B&N also lowered its predictions for EBITDA (earnings before interest, taxes, depreciation, and amortization) for fiscal 2018 to between $140 million to $160 million. Earlier estimates from the chain placed EBITDA at $180 million.

B&N blamed the soft holiday sales on a slow December, claiming that comp store sales were improving into November but had weakened in December. The largest decline came in B&N’s gift, music, and DVD categories; B&N said this drop accounted for nearly half of the comp store sales decline. Sales of books fell 4.5%, compared to one year ago.

B&N has been looking for ways to raise sales, including the possibility of opening new stores. However, in its earnings update, the retailer pointed only to continuing its “aggressive expense management program.”