Analyst Downgrades: Chipotle, Agios, bluebird bio

Analysts are weighing in on burrito chain Chipotle Mexican Grill, Inc. (NYSE:CMG), as well as biotechs Agios Pharmaceuticals Inc (NASDAQ:AGIO) and bluebird bio Inc (NASDAQ:BLUE).  Here's a quick roundup of today's bearish brokerage notes on CMG, AGIO, and BLUE.

• An E. coli outbreak continues to plague CMG, with the shares down another 7.1% today at $521.24, touching an annual low of $515 earlier. The company on Friday indicated the outbreak has hurt recent sales by roughly 22%, and subsequently cut its full-year guidance. Fourteen brokerage firms have since reduced their price targets on the stock, with the lowest mark coming from Maxim, which set its target at $495 -- in new-low territory. Elsewhere, it looks like recent option bears are making out quite well. Chipotle Mexican Grill, Inc.'s 10-day put/call volume ratio at the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX) comes in at 1.21 -- higher than 65% of all other readings from the past year. 

• AGIO is off 12.3% this morning at $54.54, and already hit an annual low of $50.38, after the firm presented data on its blood disease agent AG-221. The stock is no stranger to underperformance, having trailed the S&P 500 Index (SPX) by almost 27 percentage points in the past three months. Leerink has certainly seen enough, lowering its opinion to "market perform" from "outperform," and reducing its price target to $62 from $105. Meanwhile, short sellers are likely cheering. Almost 16% of Agios Pharmaceuticals Inc's float is sold short, representing over six days' worth of buying power, at normal daily volumes. 

• BLUE is also moving lower, dropping 30.2% to hit $25.19, as the company presented some underwhelming drug data of its own. Specifically, bluebird bio Inc's blood disorder treatment, LentiGlobin BB305, failed to live up to expectations in recent trials. Analysts are reacting quickly, with Morgan Stanley lowering its outlook to "equal weight" from "overweight," and slashing its price target to $69 from $143. Three other brokerage firms also lowered their price targets, and more bearish notes could be in store for BLUE. That is, all 13 analysts covering the security still say it's a "buy" or better, even though it's been a technical laggard.