U.S. senators from both parties have expressed skepticism that a proposed merger between grocery giants Kroger and Albertsons will lower prices for consumers. But the CEOs of Kroger and Albertsons insisted Tuesday that there will still be competition. They told a hearing that a merger will help them counter growing rivals like Walmart, Costco and Amazon. Kroger announced its plan to acquire Albertsons for $20 billion in mid-October. Together, the companies would control about 13% of the U.S. grocery market. Lawmakers said the combined company will have to divest stores in places where they compete, which will likely raise prices. But Kroger’s CEO said it has lowered prices after past mergers.