We are fast approaching the end of 2019 and it’s been a stellar year so far for the Wall Street. The S&P 500 hit a record high of 3,200 for the first time when just two weeks are left in the calendar year. The index is up now 27.7% (read: Wall Street to See Best Year Since 2013: Will ETF Rally Last?).Key events of this year that drove the markets were three Fed rate cuts, massive global policy easing in the second half, announcement of the phase-one U.S.-China trade deal after almost two-years of wrangling, a deal on USMCA and the easing of Brexit uncertainty.Against this backdrop, below we highlight a few ETF areas that have been the winners in 2019.Clean EnergyInvesco Solar ETF TAN, Invesco WilderHill Clean Energy ETF PBW and ALPS Clean Energy ETF ACES added about 63.8%, 57.2% and 50% this year. Clean energy ETFs have ridden higher this year despite President Trump’s inclination toward booting fossil-fuel energy. Going by an International Energy Agency (IEA) report, worldwide supplies of renewable electricity are expected to expand 50% in the next five years (read: Is TAN ETF a Solid Pick for 2020?).A transition toward 100% clean electricity is in process in the United States. China is a major player building a green environment. Almost half of the European Union’s (EU) 28 member states have already reached or are about to touch their 2020 renewable energy targets. All these explain a rally in clean energy ETFs.SemiconductorThe phase-one U.S.-China trade deal, a 5G boom and rising consumer spending on technology have propelled the sector. Expectations of higher smartphone sales have given an added boost. IDC expects the smartphone market to record 1.5% growth in 2020, after three straight years of global contraction. Investors should note that not only semiconductor, the entire tech space has rallied this year. In fact, technology is on its way to record the best year since 2009.VanEck Vectors Semiconductor ETF SMH (up 61.9%), SPDR S&P Semiconductor ETF XSD (up 61.4%), iShares PHLX Semiconductor ETF SOXX (up 60.3%) and First Trust Nasdaq Semiconductor ETF FTXL (up 59.2%) have proven to be the clear winners.BiotechThe Santa rally for the biotech space started long before December, thanks to loads of mergers and acquisitions, positive drug data and FDA approvals. Trade tensions are not likely to have a major impact on biotech. Investors can thus buy Virtus LifeSci Biotech Clinical Trials ETF BBC (up 58.5%) and ALPS Medical Breakthroughs ETF SBIO (up 50.8%) deserve special mention.PalladiumPalladium prices have been on a tear for two years. Pure-play Palladium ETF Aberdeen Standard Physical Palladium Shares ETF PALL added about 51.7% in 2019. The rally has mainly been backed by growing global demand and stagnating supply. The Palladium market is on its way to an eighth consecutive year of deficit in 2019, according to specialty-chemicals company Johnson Matthey, as quoted MarketWatch. Amid muted supplies, demand has been on the rise on increased consumption of gasoline engines. Stringent emission control norms have been fueling demand for Palladium-using petrol-fueled cars as governments around the world look to fight climate change (read: Will Palladium ETF's 2019 Rally Continue Next Year?).Home BuildingLow mortgage rates have worked wonders for housing stocks this year. With the Fed being dovish, this rate-sensitive sector has every reason to outperform. Plus, solid corporate earnings and lack of direct correlation with the U.S.-China trade scenario have benefited the sector. iShares U.S. Home Construction ETF ITB has added about 48.5% this year(read: After a Stellar 2019, Housing ETFs Set for a Sturdy 2020).Want key ETF info delivered straight to your inbox?Zacks’ free Fund Newsletter will brief you on top news and analysis, as well as top-performing ETFs, each week. Get it free >> Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report iShares U.S. Home Construction ETF (ITB): ETF Research Reports Invesco Solar ETF (TAN): ETF Research Reports Aberdeen Standard Physical Palladium Shares ETF (PALL): ETF Research Reports iShares PHLX Semiconductor ETF (SOXX): ETF Research Reports SPDR S&P Semiconductor ETF (XSD): ETF Research Reports Invesco WilderHill Clean Energy ETF (PBW): ETF Research Reports VanEck Vectors Semiconductor ETF (SMH): ETF Research Reports ALPS Medical Breakthroughs ETF (SBIO): ETF Research Reports First Trust NASDAQ Semiconductor ETF (FTXL): ETF Research Reports Virtus LifeSci Biotech Clinical Trials ETF (BBC): ETF Research Reports ALPS Clean Energy ETF (ACES): ETF Research Reports To read this article on Zacks.com click here. Zacks Investment Research Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report