Devitt points to economic trends, hotel consolidations, and direct travel bookings as main reasons for the downgrade.
"There's an aggressive campaign of driving traffic directly to sites allowing hoteliers to manage down their distribution costs," Devitt said on CNBC's "Halftime Report".
Devitt placed a $53 price target on TripAdvisor and $95 price target on Expedia.
—By CNBC Producer Bree Kelly. Follow her on Twitter @Bree_Kelly