What is the best measure of a mutual fund's performance?

The best measure of a mutual fund's performance is total return. Total return accounts for all aspects of a fund's performance, including capital gains, dividends, and interest income over a specific period. By looking at the total return, investors can assess how well their investments have performed compared to benchmarks or other investment options.

Net asset value reflects the value of a fund's underlying assets, but it doesn’t provide a complete picture of performance over time since it doesn’t consider how the fund has grown or generated income for investors. Annual yield can indicate how much income a fund generates relative to its price, but it does not encompass all returns, especially capital appreciation. The expense ratio provides insights into the costs associated with managing the fund, but this is more about costs than overall performance.

In summary, total return is the most comprehensive metric for evaluating a mutual fund's performance, as it incorporates all of the components vital to an investor's overall financial outcome.