GrubHub shares can increase about 75% through 2021 to roughly $100 per share, William Blair analyst Ralph Schackart tells investors in a research note. Credit Suisse this morning downgraded the stock to Neutral. The restaurant pick-up and delivery platform is down 1% to $55.30 in premarket trading. The analyst says he's received many questions following GrubHub's recent acquisitions of Foodler, OrderUp and Eat24, regarding its potential size over the next five years. Despite "fierce" competition with other online food providers, GrubHub's primary competitor still remains the paper menu, Schackart argues. His long-term model has GrubHub having only about 5% market share in 2022, or an estimated $8B in gross food sales, of the estimated $142B food delivery/takeout market. The analyst has an Outperform rating on the shares.