ETFs track an index, and there is a huge range of indices. They have much lower 'expense ratios' (that's how the management fees are named for ETFs). An ETF based on the S&P 500 allows you to gain exposure to a wide and diversified portfolio of stocks. The first bond funds were issued by iShares in 2002. They recently passed $1 tn in assets.
Key learning objectives:
Understand the uses of ETFs
Understand the historical developments of ETFs and asset classes