Dollar Tree swung to a surprise fourth-quarter loss and will close nearly 1,000 stores after the discount retailer slashed the value of a rival chain it acquired almost a decade ago. Dollar Tree plans to close about 600 Family Dollar stores in the first half of this year and 370 Family Dollar and 30 Dollar Tree stores over the next several years. Dollar Tree acquired Family Dollar for more than $8 billion in 2015 after a bidding war wi