 Shares of Big Lots Inc. BIG, -6.87 dove 7.1 toward a 2-year low in morning trading Tuesday, after the discount home essentials retailer disclosed Chief Merchandising Officer Jack Pestello had been terminated without cause. The disclosure comes after the stock tumbled 12.1 on Friday, after the retailer reported a surprise first-quarter loss and big sales miss and provided a downbeat gross margin outlook, as sales trends materially slowed in April. 