Wall Street was upbeat last week. The S&P 500 (up 1.52%), the Dow Jones (up 0.96%), the Nasdaq Composite (2.82%) and the Russell 2000 (up 5.1%) – all returned nicely last week. The FDA granting the first full U.S. approval to Pfizer PFE /BioNTech’s (BNTX) coronavirus vaccine, Comirnaty (BNT162b) has boosted investors’ confidence in economic reopening-friendly sectors.This is because the full approval will likely help mitigate the ongoing surge in the COVID-19 Delta variant and lead to a continued reopening of the economy. Wells Fargo Securities head of equity strategy Christopher Harvey has boosted optimism among investors by upgrading its year-end price target for the S&P 500 to 4,825 (per a CNBC article).Tech stocks too rallied last week. The tech-heavy Nasdaq Composite Index topped 15,000 for the first time ever driven by continued strength in tech stocks like Microsoft (MSFT), Nvidia (NVDA) and Alphabet (GOOGL). Additionally, strong corporate profit growth and ultra-easy monetary policies remain the major catalysts (read: Nasdaq Tops 15K for First Time: 5 Best Stocks in the ETF).Against this backdrop, below we highlight a few sector ETFs.ETFs in Focus EnergyOil prices soared last week, breaking a seven-day losing streak – the worst since 2019. News of zero new cases in China, U.S. FDA’s full approval of Pfizer-BioNTech Covid-19 vaccine, no new flare-up in taper talks, the moderate strength in the greenback and bargain hunting led to the oil price gains (read: Is This the Time for Crude Oil & Energy ETFs?).S&P Oil & Gas Exploration Bull 3X Direxion GUSH – Up 28.9%Microsectors U.S. Big Oil Index 3X ETN (NRGU) – Up 28.15%BiotechThe biotech space is once again gaining on positive COVID-19 vaccine update. The FDA’s first full U.S. approval to Pfizer /BioNTech’s coronavirus vaccine boosted biotech ETFs (read: Pfizer Vaccine Approval Triggers a Surge in Biotech ETFs).S&P Biotech Bull 3X Direxion LABU – Up 24.96%Silver MinersChances of upbeat industrial activities and a subdued greenback have favored silver prices this year, which in turn benefited silver mining stocks.ETFMG Prime 2X Daily Junior Silver Miners ETF SILX – Up 19.41%China InternetChinese technology stocks surged last week after many weeks of sell-off brought about by Beijing’s regulatory crackdown. Superb results reported by JD.com (JD) and Pinduoduo (PDD), as well as share buyback announcement by Tencent (TCEHY) are helping the rebound. Despite rising uncertainty, some investors have continued to pour money into these beaten down stocks and ETFs (read: Should You Buy China Tech Stocks & ETFs Now?).CSI China Internet Index Bull 2X Direxion CWEB – Up 18.82%Gold MinersGold prices gained due to a weakened U.S. dollar and investors speculated on the Federal Reserve deferring plans to taper its accommodative monetary policies. Hence, mining stocks and ETFs gained last week.Microsectors Gold Miners 3X ETN GDXU – Up 18.8%High-BetaThe FDA-Pfizer news, strong earnings and global optimism have helped high-beta stocks and ETFs last week. Additionally, the economy has returned to the pre-pandemic level with the GDP rising 6.5% annually in the second quarter, indicating a sustained recovery from the pandemic-induced recession (read: High-Beta ETFs to Bet on Renewed Market Momentum).S&P 500 High Beta Bull 3X Direxion HIBL – Up 18.67%SemiconductorsSemiconductor ETFs have been in the sweet spot thanks to surging demand for chips from manufacturers of everything from smartphones to cars, laptops, PCs, video games and data centers. Global semiconductor industry sales jumped 29.2% year over year to $44.5 billion in June 2021, the Semiconductor Industry Association (“SIA”) reported on Aug 2 citing data compiled by the World Semiconductor Trade Statistics.Semiconductor Bull 3X Direxion SOXL – Up 16.99% Breakout Biotech Stocks with Triple-Digit Profit Potential The biotech sector is projected to surge beyond $2.4 trillion by 2028 as scientists develop treatments for thousands of diseases. They’re also finding ways to edit the human genome to literally erase our vulnerability to these diseases. Zacks has just released Century of Biology: 7 Biotech Stocks to Buy Right Now to help investors profit from 7 stocks poised for outperformance. Recommendations from previous editions of this report have produced gains of +205%, +258% and +477%. The stocks in this report could perform even better.See these 7 breakthrough stocks now>>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 Pfizer Inc. (PFE): Free Stock Analysis Report Direxion Daily S&P Oil & Gas Exp. & Prod. Bull 2X Shares (GUSH): ETF Research Reports Direxion Daily S&P Biotech Bull 3X Shares (LABU): ETF Research Reports Direxion Daily Semiconductor Bull 3X Shares (SOXL): ETF Research Reports Direxion Daily CSI China Internet Index Bull 2X Shares (CWEB): ETF Research Reports Direxion Daily S&P 500 High Beta Bull 3X Shares (HIBL): ETF Research Reports MicroSectors Gold Miners 3X Leveraged ETNs (GDXU): ETF Research Reports ETFMG Prime 2x Daily Junior Silver Miners ETF (SILX): ETF Research Reports To read this article on Zacks.com click here. Zacks Investment Research