Doug Anmuth, an analyst at JPMorgan, downgraded to "neutral"from "overweight" on user and advertising challenges, TheFly.comreported, citing a post-earnings research note.

Citing the company's first-quarter , the analyst said productchanges have been slower and less impactful than expected. Anmuth also loweredthe price target on the company's stock to $18 from $26.

Further, the analyst said the microblogging website isfacing increased competition from other social networking services, such asFacebook Inc.'s coreNewsfeed, Instagram and Messenger, and Snapchat.