Investing
Fund manager
The professional who decides what a mutual fund buys and sells on behalf of investors.
A fund manager runs an active fund, researching and picking which stocks or bonds to hold to meet the fund's goal.
Their skill is what you pay the higher expense ratio for in an active fund. In an index fund, there is barely any active decision-making.
A manager leaving can change a fund's character, so it is worth noting, though most people overestimate how much any single person matters over decades.
For example
When a star fund manager switches companies, investors often debate whether to follow them, even though the index quietly beats most of them anyway.