Twitter shares have climbed more than 40% over the last two weeks Because of the immense run-up in Twitter Inc (NYSE:TWTR) shares, one of the company's biggest bulls has actually downgraded it. Jay Yarow of Business Insider reports that SunTrust Robinson Humphrey analyst Robert Peck downgraded Twitter to Hold. He did maintain his $50 per share price target, but he said that since the stock was 20% more than his target, he decided to downgrade it.