The largest U.S. residential solar installer SolarCity (SCTY - Snapshot Report) has made a nice comeback at the start of the final month of 2015. The stock jumped over 19% in the last week.

The massive gain for this solar firm came on the back of the news that options trader Jon Najarian has added SCTY in his portfolio after "spotting unusual options activity.” As SolarCity strongly bounced off its 52-week low of $24.07 reached on November 11, Najarian speculates that the stock might be ready to soar further (read: Solar ETFs to Watch Following Q3 Results).

This has spread bullishness in the ETF world, especially among funds having the largest allocation to this solar firm. These products are, namely Guggenheim Solar ETF (TAN - ETF report), Market Vectors Solar Energy ETF (KWT - ETF report) and First Trust NASDAQ Clean Edge Green Energy Index Fund (QCLN - ETF report). The trio currently has about 5.4%, 4.9%, and 4.3%, allocation in SolarCity, respectively. TAN stole the show gaining 4.4% in the last two days while KWT and QCLN added 1.5% and 2.9%, respectively.

While TAN and KWT target the solar space of the alternative energy world, QCLN provides global exposure to companies that are primarily engaged in the manufacturing, development, distribution and installation of emerging clean-energy technologies including solar photovoltaics, biofuels and advanced batteries (read: A Primer on Alternate Energy ETFs).

SolarCity has been struggling since the start of the year thanks to vicious oil trading and investors’ misconception that oil price and solar market fundamentals are directly related to each other. The woes deepened when the company reported disappointing third-quarter results on October 29 after the closing bell. Before registering a 19% gain, shares of SCTY tumbled 46.2% from a year-to-date look and 24% since the earnings announcement.

Investors should also note that the stock has a Zacks Rank #4 (Sell) with a poor Growth, Value and Momentum style score of ‘F’ each. These suggest that gains for SCTY might not last long and could see further pains, which could push the ETFs down. From a year-to-date look, TAN, KWT and QCLN are down 18.7%, 13.9%, and 11.1%, respectively (see: all the Alternative Energy ETFs here).

However, the solar industry has a solid Zacks Rank in the top 10% at the time of writing. The industry fundamentals are also encouraging with growing demand for renewable sources, efficient alternative energy application and Obama’s ‘Climate Change Action Plan’.