NEW YORK — Best Buy reported a drop in sales during the holiday season and the company now expects a wider drop in fourth-quarter revenue, partly on weak mobile phone and personal device sales.

Domestic same-store-sales, a key measure of a retailer's health, fell 1.2 percent in the nine-week period ended in Jan. 2 compared with growth of 3.4 percent during the same period a year prior. Online revenue rose 12.6 percent, compared with growth of 13.4 percent a year ago.

Looking ahead, the electronics store operator expects a 4 percent drop in revenue for its fourth quarter.

Shares of Best Buy Co., which is based in Minneapolis, dropped $2.52, or 8.6 percent, to $26.74 in premarket trading about 90 minutes ahead of the market opening Thursday.