Among the ETFs of Standard & Poor's 500 Index, there are Standard & Poor's 500 Index double bulls (SPY)/ double bulls ProSharesUltraS, while the reverse ETFs are dollar ETF-PowerSharesDB(UUP) and double short ETF: Euro ETF-ProShares double short (EUO). It is noteworthy that, in addition to the above-mentioned dollar and euro ETFs, there are some other currency ETFs worthy of attention: RMB-related ETFs: RMB ETF-WisdomTreeDreyfus(CYB), which tracks the short-term exchange rate changes of RMB; If the RMB appreciates, its income will increase accordingly. Sterling ETF: Sterling ETF-CurrencyShares(FXB). Yen-related ETF: shares Japan ETF (FXY) with multi-yen currency; Double short ETF-ProShares(YCS). Swiss franc related ETF: long Swiss franc ETF-CurrencyShares(FXF). Canadian dollar related ETF: Do multi-Canadian dollar ETF-CurrencyShares(FXC). Australian dollar related ETF: Do multi-Australian dollar currencies share the Australian dollar ETF (FXA)? 3. The crude ETF ETFs that do more oil are: American Petroleum Fund (NYSE: USO), which is currently the largest crude oil ETF in the world with a historical scale of 4.29 billion US dollars. The ETF is listed on the New York Stock Exchange, and its investment targets are West Texas Intermediate (WTI) and some short-term government bonds. However, USO's position is not limited to WTI crude oil futures, but may also hold ICE's low-sulfur light crude oil, heating oil, gasoline, natural gas and other petroleum fuel futures. Etfs that do more oil include UnitedStatesbrentoilFundlp (NYSE: BNO), which mainly tracks the daily price trend of Brent crude oil. Other investments in the portfolio include other oil-related futures contracts, forward contracts, swap contracts, cash, cash equivalents and US government debt. In addition, there are iPathS gold ETF-PowerShares DB (DGP); Gold ETF-ProShares double bulls (UGL); Gold ETF-PowerSharesDB Double Short (DZZ) and Gold ETF-ProShares Double Short (GLL). Generally speaking, unlike other ETFs mentioned above, the structure of gold ETFs is similar, which is based on tracking the exogenous gold price. Therefore, the choice of gold ETF can be judged by combining the management cost of the fund. Among them, GraniteSharesGoldTrust(BAR), which was just established the year before last, has an expense ratio of only 17, so it is a low-cost fund in the market at present. In contrast, GLD charges 40 basis points and iSharesGoldTrustETF charges 25 basis points. In addition, low-cost gold ETFs include SPDRGoldMiniSharesTrust(GLDM) and Perth Mint Physical Gold ETF(AAAU), both of which charge 18 basis points. It is worth noting that some analysts suggest that the proportion of gold should not exceed 3-5% in a diversified portfolio, and investors can allocate gold with a small amount of funds, but this is only to cope with short-term market events, and there is no reason to buy gold in large quantities. In addition to gold, silver ETF is also worthy of attention. Earlier, Hou Wenbin, chief analyst of Baiyin.com, China, wrote in Investing.com Weiying Caijing that it is expected that by the end of this year, there will be more speculative purchases through short selling and/or long accumulation. This will push up Comex's spot silver price, thus enhancing the value of iShares Silver Trust ETFSLV. Silver reverse ETFs include silver ETF-ProShares double long (AGQ) and silver ETF-ProShares double short (ZSL). 5. Bond ETF In terms of national debt, the US Treasury 20+ Year ETF-iShares(TLT) is the most popular long-term US Treasury ETF in the US market, and it is also an active variety of bond ETFs. Its continuous investment return rate of 12 months is about 17.8 1%, and the dividend yield is about 2.75%. This product contains hundreds of long-term treasury bonds and has good liquidity. Correspondingly, there are also reverse ETFs: short-term treasury bonds -ProShares(TBF), double-length treasury bonds-ProShares (UBT); Long-term treasury bonds are double short-term stocks (TBT), triple long-term treasury bonds -Direxion(TMF) and triple short-term treasury bonds -Direxion(TMV). Among them, US Treasury 7- 10 ETF-iShares(IEF) is the largest and most active US Treasury ETF, with small volatility, which is not suitable for risk-oriented investors. IEI is also the representative of medium-term treasury ETF, holding 3-7-year bonds and paying dividends once a month, with a dividend ratio of about 1.35%. In addition, there is a short-term U.S. Treasury ETF, which tracks 1-3-year U.S. Treasury bonds: U.S. Treasury bonds 1-3-year ETF(SHY), which is also the largest in the Treasury ETF, reaching1200 million dollars. Due to the short maturity date, the dividend rate of this product will be relatively low, and it will be paid once a month. The dividend yield in the latest year is about 0.48%. And ultra-short-term bond ETFs: short-term US Treasury bonds ETF(SHV), tracking 1 ~ 12-month maturity bonds. Investors can also focus on local government bonds ETF-iShares(MUB) and invest in American investment-grade local government bonds. Local government bonds can be exempted from federal tax, so the yield is lower than ordinary bonds. In addition to the above-mentioned treasury bonds and treasury bonds ETFs, investors can also pay attention to some corporate bond ETFs. Among them, the investment portfolio of American investment-grade corporate bonds -iShares(LQD) includes 600 investment-grade corporate bonds with good liquidity, while the American total bond market ETF-Vanguard(BND) and the American total bond market ETF-iShares(AGG) are the comprehensive bond indexes of the United States that track Barclays Capital, including American investment-grade bonds.