A Raymond James analyst downgraded shares of the wireless carrier to ‘‘market perform’’ from ‘‘outperform,’’ questioning the strength of the stock’s recent rise. The shares have more than doubled in value this year. Sentiment toward the stock among analysts “appears to be pessimistically slanted,” Schaeffer’s Investment Research reported on its website, with 10 “buy” or better ratings, compared to 12 “holds” and four “sell” or worse recommendations. Thomson Reuters reports an average 12-month price target of just $5.11.