In selecting mutual funds, most investors know to check the expense ratio, the standard measure of how costly a fund is to own. U.S.-stock funds pay an average of 1.31% of assets each year to the portfolio manager and for other operating expenses, according to Morningstar Inc. The minimum initial investment for most mutual funds ranges from $1,000 to $10,000 but there are no investment minimums for additional purchases. When you buy or redeem a mutual fund, you are transacting directly with the fund, whereas with ETFs and stocks, you are trading on the secondary market. Example: Let’s say you own a mutual fund that is valued at $10 per share. It has a gross return of 10%, meaning its total investment return was $1 per share. It has a gross return of 10%, meaning its total investment return was $1 per share.