ETFs trade on the stock exchange like stocks, so they're value fluctuates like stocks throughout the day and you can buy and sell at any point during days the ETFs is open. Mutual fund shares you buy from the funds company. They get priced daily after the trading day is over, so you can place buy or sell orders throughout the day but they're executed after the market closed at that day's price. Also, mutual funds charge various fees, which in many cases includes sales charges that could exceed 5% (so-called "loads"). I avoid load funds like the plague. Research shows their pre-load returns average the same as those of no-load funds, so the load doesn't buy you anything but a built-in loss.