Shares of GrubHub dropped more than 2 percent in Wednesday morning trade after a report said Facebook plans to add a food-delivery option to its app. The stock ended the day roughly flat.
The social media giant is providing new features to keep users engaged as personal sharing on its platform has declined. Among the several new additions, it will start allowing people to order food, according to The Wall Street Journal.
If successful, Facebook could threaten GrubHub's dominance in the food delivery business. Grubhub's stock is up more than 73 percent for the year to date; GrubHub reported a 37 percent year-over-year revenue growth in the second quarter.
GrubHub is expected to announce its third-quarter earnings on Oct. 26 before the market opens.
Facebook shares ended the day about 1 percent higher.
CNBC has reached out to GrubHub and Facebook for comment.