UPDATE: UBS Downgrades Twitter from Neutral to Sell

UBS downgraded Twitter

from Neutral to Sell and lowered the price target from $45 to $42 in a research note Thursday. The firm's Eric J. Sheridan lowered his estimates due to negative trends in user growth/engagement and the lack of upside in estimates over coming quarters. Sheridan said, "Twitter remains one of the most expensive stocks in our universe - an out performance that we believe is unlikely to be sustained given questions raised by the earnings report." "A lack of mainstream adoption or a more simplified use case was a worry of ours coming out of the IPO & seems to have come to the fore faster than we had anticipated," according to Sheridan. TWTR is down over 20 percent at last check; the shares have lost more than 13 points Thursday, and the stock is currently trading around $52.45.