Shares of Twitter Inc. /zigman2/quotes/203180645/composite TWTR -3.30% are up about 2% in premarket trading Wednesday after Pivotal Research Group analyst Michael Levine upgraded the stock to buy from hold with a target price of $59.75. "Investors will admittedly need to underwrite a high multiple with a company that has had some historical executional hiccups," Levine wrote. "We believe it will be warranted if the ship is moving in the right direction as we suspect." He is upbeat about the company's potential to capitalize on the Olympics next year, as well as the possibility of some real momentum with Twitter's direct-response ad offerings. "While we still have some question marks about the [direct-response] business, we see signs of life," he wrote. "Additionally, we think sentiment is by far the most negative in our coverage and as a result, the rubber band for stock out-performance the greatest." Shares have added 35% over the past three months as the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.68% has risen about 6%.