When people think about traditional mutual funds they typically think about funds known as “open ended funds.” They are the most commons funds. Shares of the fund are bought or sold though the fund company. There are no limits to the number of shares that can be issued and shares prices are determined once a day, after the market closes. At that point the total value of the assets in the mutual fund are determined and divided by the number of shares. This is the “net asset value” (NAV) and everyone who buys a share on that day pays the same price and everyone who sells also gets the same price, not matter what time of the day the order to buy or sell has actually been entered.
“Exchange Traded Funds” (ETFs) are newer but have become popular because they are bought and sold like a stock and are traded on major exchanges. The price of the shares can fluctuate during the day and the price that an investor pays for the shares can be different from minute to minute, just like the price of a stock will fluctuate during the day. That means that an ETF can be bought in the morning and sold in the afternoon for a profit or a loss depending on the change in value. The market price of an ETF is kept near the NAV by large institutional investors who will detect any difference between the NAV and the actual share price and use “arbitrage” to make that difference go away.
Because ETFs are more flexible in terms of trading strategy, they have become very popular with many active investors and speculators. In addition, because many ETFs are “passive” funds they often have lower expense ratios than many traditional mutual funds.
There are a number of other issues that an investor should be aware of with ETFs such as liquidity, commissions to trade, the bid-asked spread, and the viability of any specific ETF.
As always, consult your investment advisor.