Shares in 99 Cents Only Stores dropped early Thursday after the company posted an unexpected fourth-quarter loss Wednesday afternoon.

The discount retailer’s loss for the quarter ended March 29 increased to $4.4 million (-6 cents per share), compared to a loss of $1 million (-2 cents) in the same period a year earlier. Analysts polled by Bloomberg were expecting a break-even quarter.

Sales gained 4.5 percent to $291 million, which was in line with Wall Street predictions, while same- store sales increased 1.5 percent for the quarter.

99 Cents Only blamed the reduced profit on the loss of merchandise from employee theft which the company said was $5.5 million higher than expected.

Chief Executive Officer Eric Schiffer said the company is using loss-prevention software and other measures to try to reduce theft.

Shares in 99 Cents Only were down 4.2 percent to $7.56 in early trading Thursday.