RATINGS CHANGES

Aircastle (AYR) - Get Report was downgraded to market perform from outperform at Wells Fargo. Analysts see better relative value elsewhere, Wells said. 

Baxter (BAX) - Get Report was upgraded to overweight from neutral at Piper Jaffray. $58 price target. The company can continue to delivery solid free-cash flow, Piper said. 

Chipotle Mexican Grill (CMG) - Get Report was upgraded to overweight from neutral at JPMorgan. $510 price target. Comp-store sales are set to sequentially improve, JPMorgan said. 

3D Systems (DDD) - Get Report was upgraded to buy from underperform at Bank of America/Merrill Lynch. $26 price target. The new CEO can change the company's direction and strategy, analysts said. 

Lennox (LII) - Get Report was downgraded to sector weight from overweight at Keybanc. The valuation isn't as attractive, following strong multiple expansions, Keybanc said. 

Mercer (MERC) - Get Report was upgraded to buy at TheStreet Ratings. You can view the full analysis from the report here: MERC.

MDC Partners (MDCA) - Get Report was upgraded to outperform from market perform at Wells Fargo. Earnings estimates were also increased, given recent business momentum, Wells said. 

Omnicom (OMC) - Get Report was downgraded to market perform at Wells Fargo. The valuation isn't as attractive, with shares up 11% year-to-date, Wells said. 

Red Hat (RHT) - Get Report was upgraded to overweight at Pacific Crest. $88 price target. Core moment remains solid and the company can delivery higher free-cash flow, Pac Crest said. 

Summit Materials (SUM) - Get Report was initiated with a sell rating at TheStreet Ratings. You can view the full analysis from the report here: SUM.

This article was written by a staff member of TheStreet.