24/7 Wall St.

The S&P 500 hit yet another new all-time high this week, but many investors remain worried about buying the top or getting caught in a sell-off. 24/7 Wall St. reviews dozens of analyst research reports each morning for new ideas. Some of the reports cover stocks to buy, but some cover stocks to sell or to avoid. These are this Wednesday’s top analyst upgrades, downgrades and initiations seen from Wall Street research firms.

Alkermes PLC (NASDAQ: ALKS) was started as Outperform with a $57 price target at Credit Suisse.

Apollo Education Group Inc. (NASDAQ: APOL) traded lower after earnings, but the for-profit education player’s shares were upgraded to Outperform from Market Perform at Wells Fargo. Zacks said Tuesday night that its rating was slipping to a Strong Sell rating.

ArcelorMittal (NYSE: MT) was downgraded to Neutral from Outperform at Credit Suisse.

Cognizant Technology Solutions Corp. (NASDAQ: CTSH) was raised to Buy from Neutral at UBS.

Comerica Inc. (NYSE: CMA) was raised to Market Perform from Underperform at Wells Fargo.

Edison International (NYSE: EIX) was downgraded to Hold from Buy at Argus in a valuation call.

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Essex Property Trust Inc. (NYSE: ESS) was downgraded to Neutral from Buy at Goldman Sachs.

Ford Motor Co. (NYSE: F) was started as Neutral at Nomura.

General Motors Co. (NYSE: GM) was started as Reduce at Nomura.

Goldman Sachs Group Inc. (NYSE: GS) was reiterated as Outperform with a $185 price target (versus a $165.92 close) at Credit Suisse, but the firm lowered its 2014 earnings expectations by almost 3% due to elevated litigation expenses.

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Imperial Oil Ltd. (NYSE: IMO) was downgraded to Underperform from Neutral at Bank of America Merrill Lynch.

Intuitive Surgical Inc. (NASDAQ: ISRG) is getting a serious upgrade after its robotic device was granted FDA approval. JMP Securities is taking its rating up to Outperform from Underperform, and the price target was more than doubled — to $700 from $320 — making it the highest of all price targets among the two-dozen or so analysts that follow it. Its stock was up 12.7% to $493.60 on Tuesday, against a 52-week range of $351.14 to $516.07.

Medicines Co. (NASDAQ: MDCO) was downgraded to Neutral from Overweight at Piper Jaffray, and the price target was slashed to $29 from $41 after Tuesday’s big drop.

Textron Inc. (NYSE: TXT) was started as Overweight with a $44 price target at J.P. Morgan.