Last week was a modest one for U.S. markets with SPDR Dow Jones Industrial Average ETF DIA losing 0.1%, SPDR S&P 500 ETF SPY gaining 0.4%andthe Nasdaq-based Invesco QQQ Trust QQQ advancing 0.7%. Key events of the week were a slew of earnings releases, progress on Brexit and an upheaval in the oil patch.Against this backdrop, we highlight a few ETF winners and losers of last week.ToppersUnited States Natural Gas UNG — Up 17.2% per xtf.comLike in most winters, natural gas prices started receiving warmth from the chills this year. Per EIA, natural gas inventory was 15.6% lower than the five-year average and 14% lesser than the year-ago level (read: Natural Gas ETFs to Heat Up on Winter Chills?).The cold snap boosts electricity or heating demand across the region, putting focus on natural gas. According to AccuWeather, the United States may witness the El Nino weather pattern this winter, causing much colder-than-average temperatures in most of the Northeast, mid-Atlantic, Great Lakes and Ohio Valley of the country, particularly in January and February. This provided a boost to UNG.Franklin FTSE South Africa ETF FLZA — Up 9.8%The latest bloodbath in Wall Street, slight weakness in the greenback and political uncertainty concerning Brexit led investors to the emerging market (EM) pack, probably due to cheaper valuation. The bloc has seen immense pain in mid-2018 and investors are taking interest of late (read: Time to Buy the Beaten-Down Emerging Market ETFs?).Also, speculation that the South African Reserve Bank may hike rates at its policy meeting on Thursday boosted the already juicy carry yield offered by the rand (read: Are All of 'Fragile Five' EM ETFs Equally Frail?).Xtrackers Harvest CSI 500 China A Small-Cap ETF ASHS — Up 9.4%Like many analysts, we believe thatthe inclusion of China’s A-shares in global and emerging market indices is a great positive for this Chinese segment. Notably, MSCI added China A shares in the MSCI Emerging Markets Index and the MSCI ACWI Index in June 2018. FTSE Russell also announced the addition of mainland shares to its flagship indexes starting next June (read: Stimulus Hopes Boost China's Stocks: ETFs Gain the Most).MSCI Inc. is now considering quadrupling the weight of Chinese big-caps to 20% in its global benchmarks. MSCI also proposed the inclusion of mid-caps from 2020 and shares listed on Shenzhen's start-up board ChiNext next year. Also, policymakers’ supports like a possible cut in benchmark lending rates boosted these stocks.VanEck Vectors Indonesia ETF IDX — Up 7.3%Indonesia’s central bank surprisingly hiked rates on Nov 15 by 25 bps to 6%, after trade balance recorded a gap in October. It was the economy’s sixth rate hike this year. This in turn boosted Indonesian stocks as the move shored up its currency, put a cap on inflation and attracted yield-hungry investors.LosersUBS ETRACS S&P GSCI Credit Oil Total Return ETN OILX — Down 6.3%Weaker-than-expected U.S. sanctions on Iran and fears of waning global demand amid growth worries weighed on oil prices last week and hit the product.Morgan Stanley Cushing MLP High Income Index ETN MLPY — Down 6.1%A decline in oil prices and rising rate worries hurt this high-yielding corner of the energy sector. The fund yields 10.38% annually (read: Brent in Bear Market: 4 Country ETFs to be Cautious About).First Trust Nasdaq Retail ETF FTXD — Down 5.9%Downbeat earnings fromJ.C. Penney JCP and Dillard's DDS affected retail stocks. The J.C. Penney stock’s loss of 5.2% on Nov 16 and Dillard's fall of 14.8% on Nov 15 due to disappointing earnings rippled through the retail sector.ETFMG Alternative Harvest ETF MJ — Down 5.8%Corporate earnings worked against the marijuana ETF. Two of Canada’s top cannabis producers, Canopy Growth Corporation CGC and Tilray Inc. TLRY saw net losses, sending pot stocks spiraling down on Nov 14. To add to the woes, Canopy Growth CEO Bruce Linton sounded less optimistic about the industry’s growth in America, at least in the near term. Meanwhile, both Tilary and Cronos Group CRON reported a decline in average selling price for cannabis products (read: What Went Wrong With the Marijuana ETF on Wednesday).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 SPDR-DJ IND AVG (DIA): ETF Research Reports DEUTS-XT HV CS5 (ASHS): ETF Research Reports VANECK-INDONES (IDX): ETF Research Reports FT-NDQ RETAIL (FTXD): ETF Research Reports NASDAQ-100 SHRS (QQQ): ETF Research Reports SPDR-SP 500 TR (SPY): ETF Research Reports J. C. Penney Company, Inc. (JCP): Free Stock Analysis Report Dillard's, Inc. (DDS): Free Stock Analysis Report Canopy Growth Corporation (CGC): Free Stock Analysis Report Cronos Group Inc. (CRON): Free Stock Analysis Report Tilray, Inc. (TLRY): Free Stock Analysis Report MS-CUSH MLP HI (MLPY): ETF Research Reports R-TRC GSCI COTR (OILX): ETF Research Reports FL-FTSE SO AFR (FLZA): ETF Research Reports Macy's, Inc. (M): Free Stock Analysis Report 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