Can mutual fund prices have opening gaps? Might my order to be filled at a higher price?
Mutual funds don't work like stocks in that way. The price of a mutual fund is set at the end of each day and doesn't fluctuate during the day. So no matter when you put in your order, it will be filled at the end of the day at whatever the closing price is for that day. Here is some good information on that There is no continuous pricing of fund shares throughout the trading   day. When an investor places an order to buy or sell a fund's shares,   the order is executed based on the NAV calculated at the end of that   trading day, regardless of what time during the day the order was   placed. On the other hand, if the investor were to check the price of   his or her fund shares halfway through the business day, the price   quoted would be the previous day's NAV because that was the last time   the fund calculated and reported the value. -http://www.finweb.com/investing/how-mutual-funds-are-priced.html