Analyst Upgrades: Amazon, Yum! Brands, TerraForm Power

Analysts are weighing in on e-tailer Amazon.com, Inc. (NASDAQ:AMZN), Pizza Hut parent Yum! Brands, Inc. (NYSE:YUM), and energy issue TerraForm Power Inc (NASDAQ:TERP). Here's a quick roundup of today's bullish brokerage notes on AMZN, YUM, and TERP.

• AMZN reported record weekend sales for its electronic devices, with blowout performances by its Fire TV and tablet. Barclays responded by upping its price target to $850 from $700 -- record-high territory for Amazon.com, Inc., which closed at $664.80 yesterday, and in step with the bullish tenor of the brokerage community. The shares have more than doubled in 2015, and are up another 1% ahead of the bell. If this trend continues, it could rattle the bearish holdouts at the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX). Specifically, AMZN's 50-day put/call volume ratio of 0.94 registers above four-fifths of comparable readings from the past year, indicating traders have been buying to open puts over calls at an accelerated clip in recent months.

• Despite sliding 9% this quarter to sit just below its year-to-date flatline, YUM received an upgrade to "outperform" from "market perform" at Cowen and Company, which also boosted its price target by $11 to $88. The upbeat note -- attributed to optimism over Yum's pending spin-off of its Chinese business -- has the stock pointed 1.1% higher in pre-market trading, after closing at $72.51 on Monday. On the options front, short-term speculators have been very call-focused toward Yum! Brands, Inc. The security's Schaeffer's put/call open interest ratio (SOIR) of 0.48 indicates calls more than double puts among options expiring in the next three months. What's more, this ratio registers below 86% of comparable readings, when looking back 12 months.

• TERP has put in an embarrassing performance on the charts, alongside parent company Sunedison Inc (NYSE:SUNE). Last week, TerraForm Power Inc hit a record low of $6.73, and closed Monday just a shade higher, at $6.90. This morning, though, the stock is poised to jump 12.6% at the open, after Oppenheimer upped its opinion to "outperform," saying the "shares are currently trading well below the intrinsic value of the asset portfolio, with risk/reward at current levels substantially weighted to the upside." Meanwhile, hedge fund Appaloosa Management sent a letter to TERP directors, requesting "substantial further disclosures ... so that investors can assess the full impact of the [company's] pending transactions." In the options pits, TERP call buyers have been active of late. Specifically, the equity's 50-day ISE/CBOE/PHLX call/put volume ratio of 1.62 outranks two-thirds of all other readings from the past year.