Analyst Upgrades: Microsoft, Boyd Gaming, Sunedison

Analysts are weighing in on tech titan Microsoft Corporation (NASDAQ:MSFT), casino interest Boyd Gaming Corporation (NYSE:BYD), and solar energy concern Sunedison Inc (NYSE:SUNE). Here's a quick roundup of today's bullish brokerage notes on MSFT, BYD, and SUNE.

• MSFT is pointed 1.2% higher ahead of the bell, after falling to a close of $52.17 on Thursday. BMO began coverage on Microsoft Corporation with an "outperform" rating and $64 price target, lauding the company's move to cloud-based services, and adding to the 71% of analysts currently giving the stock a "buy" rating or better. Microsoft is reportedly testing a "Microsoft SIM card," which would allow users of Windows phones to connect to mobile networks contract-free. The stock hit a near 15-year high of $56.86 in late December, shortly after Barron's praised MSFT's prospects. Option traders have been unsurprisingly optimistic -- at the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX), the equity's 50-day call/put volume ratio of 2.29 ranks higher than 78% of the past year's readings.

• An upgrade to "overweight" from "neutral" at J. P. Morgan Securities has BYD set to pop 1.9%, after closing at $17.78 on Thursday. The brokerage also raised its price target on Boyd Gaming Corporation to $22 from $20. The stock has been trending higher for more than a year, adding 55% in 2015. Still, eight out of 10 analysts say BYD is only a "hold," leaving plenty of room for future upgrades. There's plenty of buying power on the sidelines, too -- the 13.8% of the security's available float currently sold short would take more than a week to buy back, at BYD's average pace of trading.

• After finishing a brutal Thursday down nearly 40% at $3.34, SUNE is set to rebound today, up 11.1% ahead of the open, after Axiom Securities upgraded the stock to "hold" from "sell." Sunedison Inc announced new financial moves yesterday, sending shareholders running for the exits. The stock plummeted from July to mid-November, but seemed to be on the mend until yesterday's spiral. And while 10 out of 15 analysts call SUNE a "buy," more than 45% of SUNE's available float is still sold short. And option traders have been especially bearish; the stock's 10-day put/call volume ratio on the ISE, CBOE, and PHLX is 1.07 -- higher than 88% of all readings in the last 12 months.