24/7 Wall St.

Investors frequently get to see the analyst upgrades and Buy ratings from Wall Street firms, particularly in a rising stock market. What investors often do not get to see is when analysts downgrade stocks to sell or to avoid as valuations become frothy. 24/7 Wall St. reviews many fresh research calls each and every day to find great ideas from value stocks to growth stocks to dividend stocks. We have broken out the negative analyst calls, and these are the top analyst downgrades and cautious research notes from Wall Street for Wednesday.

Coca-Cola HBC A.G. (NYSE: CCH) was downgraded to Neutral from Buy at Goldman Sachs.

Cree Inc. (NASDAQ: CREE) was downgraded to Neutral from Positive at Susquehanna and maintained as Buy but with lowered target and estimates at Sterne Agee. Cree shares are down 15% after forecasting flat LED sales with earnings.

CST Brands Inc. (NYSE: CST) was downgraded to Underperform from Neutral at Credit Suisse.

Delta Air Lines Inc. (NYSE: DAL) was downgraded to Neutral from Overweight at J.P. Morgan.

Global Payments Inc. (NYSE: GPN) was downgraded to Neutral from Overweight at J.P. Morgan.

Millennial Media Inc. (NYSE: MM) was downgraded to Hold from Buy at Canaccord Genuity.

Parexel International Corp. (NASDAQ: PRXL) was downgraded to Underperform from Neutral at Sterne Agee.

Transocean Ltd. (NYSE: RIG) was downgraded to Neutral from Buy at ISI Group.

U.S. Airways Group Inc. (NYSE: LCC) was downgraded to Neutral from Overweight at J.P. Morgan.