The basic idea of an ETF portfolio
An exchange traded fund (ETF) is a pooled investment that trades on a stock exchange, usually tracking an index, sector, commodity or bond market. An ETF portfolio simply means owning two or more of these funds in deliberate proportions. For example, an investor might hold one fund tracking a broad equity index and another tracking government bonds, and rebalance between them over time. The portfolio, not any single fund, is what determines the investor's overall exposure to markets, currencies and asset classes. Understanding the holdings inside each fund matters, because two funds can overlap heavily and give less diversification than the number of positions suggests.
- An ETF portfolio is the combined set of exchange traded funds an investor holds, weighted by allocation.
- Each ETF itself holds many underlying securities, so the portfolio's true exposure sits at the holdings level.
- Overlap between funds is common; two equity ETFs may hold many of the same large companies.
- Allocation decisions, such as the split between equities and bonds, drive most of the portfolio's behaviour.

