A potential tie-up between DoorDash and Instacart would help the delivery apps address the two biggest elephants in the room for the grocery industry: Walmart and Amazon.

The Wall Street Journal

reported on Monday that DoorDash DASH was in “advanced talks” to buy Instacart CART in a deal that would value the latter company at some $17 billion. A deal could be wrapped up as soon as this week, the Journal said, but added talks could still fall through.