UPDATE: Wells Fargo Downgrades Twitter After Examining Challenges

On Monday, Wells Fargo Securities analyst Peter Stabler downgraded Twitter, Inc. (NYSE: TWTR ) from Market Perform to Underperform based on notable risks to the company and advertisers. Wells Fargo examined Twitter's challenges including the "(1) widely varying degrees of consumer engagement, (2) discounting of engagement metrics/high costs, (3)