Dollar Tree Inc reported better-than-expected quarterly results on Tuesday, as the discount store operator benefited from higher demand for cheaper groceries and household items during a coronavirus-induced economic downturn. Shares of Dollar Tree gained 6.3% in premarket trading as the company also said it would expand its higher-priced off ring, Dollar Tree Plus, into about 500 stores starting in the spring of 2021, after an initial test in more than 100 stores. The announcement comes after rival Dollar General unveiled the launch of Popshelf stores, which are aimed at consumers spending more on non-essential items priced at $5 or less. Sales at dollar stores, which typically sell products at $1, have remained strong even after the initial panic-buying at the start of lockdowns, with high US unemployment and falling household income boosting demand for affordable cereals and vegetables. Dollar Tree Chief Executive Officer Mike Witynski said the chain was off to a good start to its holiday quarter, with same-store sales at both its labels tracking above their third-quarter levels. Same-store sales at the company’s eponymous business increased 4% in the quarter ended Oct. 31, while they rose 6.4% at Family Dollar stores. Net income rose to $330 million, or $1.39 per share, from $255.8 million, or $1.08 per share, a year earlier.