These are some of the top analyst upgrades, downgrades and initiations seen in Wall St. research calls this Wednesday.

Align Technology Inc. (NASDAQ: ALGN) cut to Underperform as Bear of the Day at Zacks.

Amgen Inc. (NASDAQ: AMGN) raised to Outperform Bull of the Day at Zacks.

Citigroup Inc. (NYSE: C) reiterated Outperform with $48 target at Credit Suisse.

Dynegy Inc. (NYSE: DYN) started as Accumulate at Tudor Pickering.

FedEx Corp. (NYSE: FDX) cut to Outperform at Raymond James.

Mattress Firm Holding Corp. (NASDAQ: MFRM) started as Buy at Citigroup.

Mondelez International Inc. (NASDAQ: MDLZ) cut to Hold at Argus.

Nike Inc. (NYSE: NKE) started as Neutral at J.P. Morgan.

OpenTable Inc. (NASDAQ: OPEN) started as Overweight with $53 target at J.P. Morgan.

Oracle Corp. (NASDAQ: ORCL) reiterated Outperform with $40 target at Credit Suisse as it said, “Headwinds Fading … So, Jump on Board!” (That was its snapshot analysis.)

Potash Corp. of Saskatchewan Inc. (NYSE: POT) and Mosaic Co. (NYSE: MOS) were both resumed with Buy ratings by Goldman Sachs.

Prosperity Bancshares Inc. (NYSE: PB) raised to Outperform at Baird.

Seagate Technology PLC (NASDAQ: STX) cut to Underweight at J.P. Morgan.

Take-Two Interactive Software Inc. (NASDAQ: TTWO) raised to Overweight with $18 target at Piper Jaffray.

Teva Pharmaceutical Industries Ltd. (NYSE: TEVA) cut to Market Perform at Leerink Swann after its investor day guidance.

Under Amour Inc. (NYSE: UA) started as Underweight at J.P. Morgan.

Volcano Corp. (NASDAQ: VOLC) cut to Neutral at Credit Suisse.

Yelp Inc. (NYSE: YELP) started as Neutral at J.P. Morgan.

Here are some other outlook pieces for the end of 2012 and 2013:

• Fortune’s Top 10 Stocks to Buy for 2013
• BofA’s 10 Defensive and Yield Stock Picks for 2013
• The Big Gold Trade: 2013 Pairing Gold Versus Miners
• S&P 500 Upside Targets for 2013 from Everyone
• Our own 2013 Alternative Energy and Cleantech Outlook for 2013

JON C. OGG