RATINGS CHANGES

American Express (AXP - Get Report) was upgraded to perform from underperform at Oppenheimer. The valuation is more attractive, Oppenheimer said. 

American Express was downgraded to hold from buy at Argus. The company is facing considerable sales challenges, Argus said.

Bristol-Myers Squibb (BMY - Get Report) was downgraded to market perform from outperform at BMO Capital. The valuation isn't as attractive, based on a $70 price target, BMO said.

Bruker (BRKR - Get Report) was upgraded to buy at Cantor Fitzgerald. $27 price target. The company can accelerate revenue growth and expand margins, Cantor said.

Cullen/Frost Bankers (CFR - Get Report) was downgraded to hold at TheStreet Ratings. You can view the full analysis from the report here: CFR.

Entegris (ENTG - Get Report) was upgraded to overweight at Pacific Crest. $14 price target. The company is attractively valued and has good long-term potential, Pacific Crest said.

Goldman Sachs (GS - Get Report) was upgraded to buy from neutral at Nomura. The valuation looks attractive, based on a $210 price target, Nomura said.

Home Depot (HD - Get Report) was upgraded to buy from hold at Deutsche Bank said. $135 price target. The valuation looks attractive, given the stock's 12% pullback from its highs, Deutsche said. 

JPMorgan (JPM - Get Report) was downgraded at Nomura. The valuation isn't as attractive, based on a $71 price target. 

Owens-Illinois (OI - Get Report) was downgraded to sell at TheStreet Ratings. You can view the full analysis from the report here: OI.

O'Reilly Automotive (ORLY - Get Report) was upgraded to buy from hold at Deutsche Bank. The valuation is attractive, given the recent market pullback, Deutsche said.

People's United Financial (PBCT - Get Report) was upgraded to neutral from underweight at Piper Jaffray. The valuation is attractive, based on a $14 price target, Piper said.

Stewart Information Services (STC - Get Report) was downgraded to hold at TheStreet Ratings. You can view the full analysis from the report here: STC.

Twitter (TWTR - Get Report) was downgraded to hold from buy at Stifel. The management shakeup is a setback in the midst of a potential turnaround, Stifel said.

Whole Foods Market (WFM) was downgraded to underperform at BMO Capital. The valuation is not attractive, based on a $23 price target, BMO said.

WestRock (WRK - Get Report) was downgraded to neutral from buy at Bank of America/Merrill Lynch. $48 price target. The company is leveraged to lower container board pricing, analysts said.

This article was written by a staff member of TheStreet.