3. Tax differences
Long-term investors who are saving for retirement should use tax-advantaged retirement accounts such as 401(k)s and IRAs. I say this not just because it's smart -- we all know minimizing taxes means more money left in your pocket -- but also because it means you can completely ignore the complicated details of the tax consequences of investing in different types of funds.
Index funds and ETFs are both extremely tax-efficient -- certainly more so than actively managed mutual funds. Because index funds buy and sell stocks so infrequently, they rarely trigger capital gains taxes for investors.
When it comes to tax efficiency, ETFs have the edge. Unlike index funds, ETFs rarely buy or sell stock for cash. When an investor wants to redeem shares, they simply sell them on the stock market, generally to another investor.
When an index fund investor wants to redeem an investment, the index fund may have to sell stocks it owns for cash to pay the investor for the shares. This means mutual funds have to realize capital gains by selling stocks, which results in capital gains (and taxes) for everyone who continues to hold the fund, even if they are currently losing money on their investment.
4. Liquidity
Liquidity, or the ease with which an investment can be bought or sold for cash, is an important differentiator between ETFs and index funds. As previously mentioned, ETFs are bought and sold like stocks, meaning you can buy or sell them anytime the stock market is open.
On the other hand, index fund transactions (like those of all mutual funds) are cleared in bulk after the market closes. So if you put in an order to sell shares of an index fund at noon, the transaction will actually take place hours later at a price equal to the value of the fund at market close. Typically, the cutoff time is 4 p.m. ET. Orders entered after the cutoff are pushed into the next day and completed at the fund's net asset value a day later.
If you consider yourself a trader, this matters. If you consider yourself a long-term investor, it really doesn't matter much at all.
