Amazon is expanding its same-day grocery delivery service to 1,000 cities and towns across the U.S., the company said Wednesday.

Amazon AMZN will broaden its grocery delivery offering to reach more than 2,300 cities and towns in the U.S. by the end of the year, the e-commerce giant said Wednesday. Amazon stock gained while shares of a rival, Instacart parent company Maplebear CART, fell sharply.

The online retail giant plans to expand the service to 2,300 U.S. locations by year’s end in its quest to compete with Walmart.