The Top 5 Most Popular Fixed-Income Funds (ETFs)

1) Vanguard Total Bond Market ETF (BND) - This ETF provides exposure to the entire U.S. investment-grade bond market, including U.S. Treasury bonds, mortgage-backed securities, corporate bonds, and other fixed-income securities. It has a low expense ratio and is a popular choice for investors who want a diversified fixed-income portfolio. The Bloomberg Barclays U.S. Aggregate Float Adjusted Index that it tracks is widely used as a benchmark for the U.S. bond market.

2) iShares iBoxx $ Investment Grade Corporate Bond ETF (LQD) - This ETF provides exposure to investment-grade corporate bonds from U.S. issuers. Investment-grade corporate bonds are issued by companies with strong credit ratings, which means that they are less likely to default on their debt. The iBoxx $ Investment Grade Corporate Bond Index that it tracks includes bonds from a wide range of industries and maturities.

3) Vanguard Short-Term Corporate Bond ETF (VCSH) - This ETF provides exposure to short-term investment-grade corporate bonds, which are bonds with maturities of 1 to 5 years. Short-term bonds tend to have lower interest rate risk than longer-term bonds, which means that their prices are less sensitive to changes in interest rates. This ETF has a low expense ratio and is a popular choice for investors who want a diversified portfolio of short-term investment-grade corporate bonds.

4) iShares TIPS Bond ETF (TIP) - This ETF provides exposure to Treasury Inflation-Protected Securities (TIPS), which are bonds that are designed to provide protection against inflation. The principal value of TIPS adjusts for inflation, which means that the interest payments and the principal value of the bond increase with inflation. TIPS are issued by the U.S. government and are considered to be relatively low-risk investments. This ETF is a popular choice for investors who want to protect their portfolio against inflation.

5) iShares National Muni Bond ETF (MUB) - This ETF provides exposure to investment-grade municipal bonds issued by U.S. states and territories, but excludes those subject to the Alternative Minimum Tax (AMT). Municipal bonds are issued by state and local governments to fund public projects, such as roads, schools, and hospitals. Municipal bonds are generally exempt from federal income tax and may also be exempt from state and local taxes, making them an attractive choice for investors who want tax-efficient income. The S&P National AMT-Free Municipal Bond Index that this ETF tracks includes bonds from a wide range of maturities and credit qualities.