Are there disadvantages to day trading ETFs?
"ETFs are well suited to day trading, but you should be mindful of the bid-ask spread. See article: Commission-free ETFs are a great way to save money, but watch the bid-ask spread too. Bid-ask spread is largely a function of liquidity, or the volume of   buyers and sellers for an asset during a particular moment in time.   ... It may be more difficult to trade certain assets that are less   liquid, where bid-ask spreads can be higher. Think some penny stocks. If you have the choice, compare the spreads of the ETF and the target stock. Longer-term ""keep & hold"" trading on ETFs tracking futures can be somewhat disadvantageous.  Futures contracts roll-over every month.  Exchange traders have to sell and buy in on the next contract.  ETFs don't reflect the price differential between the futures contract. See here for more detail on that: Positioning For An Oil ETF Rebound? Watch For Contango Contango occurs when the price on a futures contract is higher than   the expected future spot price, which creates the upward sloping curve   on future commodity prices over time. Essentially, the phenomenon   reflects a current spot price that is lower than the futures price.   ... While this phenomena is a normal occurrence in the futures market,   contango can have a negative effect on ETFs."
Your ETF will return the interest as dividends.  If you hold the ETF on the day before the Ex-Dividend date, you will get the dividend.  If you sell before that, you will not.  Note that at least one other answer to this question is wrong.  You do NOT need to hold on the Record date.  There is usually 2 days (or so) between the ex-date and the record date, which corresponds to the number of days it takes for your trade to settle.  See the rules as published by the SEC: http://www.sec.gov/answers/dividen.htm Quote driven markets are the predecessors to the modern securities market. Before electronic trading and HFTs specifically, trading was thin and onerous.  Today, the average investor can open up a web page, type in a security, and buy at the narrowest spread permitted by regulators with anyone else who wants to take the other side. Before the lines between market maker and speculator became blurred to indistinction, a market maker was one who was contractually obligated to an exchange to provide a bid and ask for a given security on said exchange even though at heart a market maker is still simply a trader despite the obligation.  A market maker would simultaneously buy a large amount of securities privately and short the same amount to have no directional bias, exposure to the direction of the security, and commence to making the market.  The market maker would estimate its cost basis for the security based upon those initial trades and provide a bid and ask appropriate for the given level of volume.  If volumes were high, the spread would be low and vice versa. Market makers who survived crashes and spikes would forgo the potential profit in always providing a steady price and spread, ie increased volume otherwise known as revenue, to maintain no directional bias.  In other words, if there were suddenly many buyers and no sellers, hitting the market maker's ask, the MM would raise the ask rapidly in proportion to the increased exposure while leaving the bid somewhere below the cost basis.  Eventually, a seller would arise and hit the MM's bid, bringing the market maker's inventory back into balance, and narrowing the spread that particular MM could provide since a responsible MM's ask could rise very high very quickly if a lack of its volume relative to its inventory made inventory too costly.  This was temporarily extremely costly to the trader if there were few market makers on the security the trader was trading or already exposed to. Market makers prefer to profit from the spread, bidding below some predetermined price, based upon the cost basis of the market maker's inventory, while asking above that same predetermined cost basis.  Traders profit from taking exposure to a security's direction or lack thereof in the case of some options traders. Because of electronic trading, liquidity rebates offered by exchanges not only to contractually obligated official market makers but also to any trader who posts a limit order that another trader hits, and algorithms that become better by the day, market making HFTs have supplanted the traditional market maker, and there are many HFTs where there previously were few official market makers.  This speed and diversification of risk across many many algorithmically market making HFTs have kept spreads to the minimum on large equities and have reduced the same for the smallest equities on major exchanges. Orders and quotes are essentially identical.  Both are double sided auction markets with impermenant bids and asks.  The difference lies in that non-market makers, specialists, etc. orders are not shown to the rest of the market, providing an informational advantage to MMs and an informational disadvantage to the trader.  Before electronic trading, this construct was of no consequence since trader orders were infrequent.  With the prevalence of HFTs, the informational disadvantage has become more costly, so order driven markets now prevail with much lower spreads and accelerated volumes even though market share for the major exchanges has dropped rapidly and hyperaccelerated number of trades even though the size of individual trades have fallen. The worst aspect of the quote driven market was that traders could not directly trade with each other, so all trades had to go between a market maker, specialist, etc.  While this may seem to have increased cost to a trader who could only trade with another trader by being arbitraged by a MM et al, paying more than what another trader was willing to sell, these costs were dwarfed by the potential absence of those market makers.  Without a bid or ask at any given time, there could be no trade, so the costs were momentarily infinite. In essence, a quote driven market protects market makers from the competition of traders.  While necessary in the days where paper receipts were carted from brokerage to brokerage, and the trader did not dedicate itself to round the clock trading, it has no place in a computerized market.  It is more costly to the trader to use such a market, explaining quote driven markets' rapid exit. "You seem to be assuming that ETFs must all work like the more traditional closed-end funds, where the market price per share tends—based on supply and demand—to significantly deviate from the underlying net asset value per share. The assumption is simplistic. What are traditionally referred to as closed-end funds (CEFs), where unit creation and redemption are very tightly controlled, have been around for a long time, and yes, they do often trade at a premium or discount to NAV because the quantity is inflexible. Yet, what is generally meant when the label ""ETF"" is used (despite CEFs also being both ""exchange-traded"" and ""funds"") are those securities which are not just exchange-traded, and funds, but also typically have two specific characteristics: (a) that they are based on some published index, and (b) that a mechanism exists for shares to be created or redeemed by large market participants. These characteristics facilitate efficient pricing through arbitrage. Essentially, when large market participants notice the price of an ETF diverging from the value of the shares held by the fund, new units of the ETF can get created or redeemed in bulk. The divergence quickly narrows as these participants buy or sell ETF units to capture the difference. So, the persistent premium (sometimes dear) or discount (sometimes deep) one can easily witness in the CEF universe tend not to occur with the typical ETF. Much of the time, prices for ETFs will tend to be very close to their net asset value. However, it isn't always the case, so proceed with some caution anyway. Both CEF and ETF providers generally publish information about their funds online. You will want to find out what is the underlying Net Asset Value (NAV) per share, and then you can determine if the market price trades at a premium or a discount to NAV. Assuming little difference in an ETF's price vs. its NAV, the more interesting question to ask about an ETF then becomes whether the NAV itself is a bargain, or not. That means you'll need to be more concerned with what stocks are in the index the fund tracks, and whether those stocks are a bargain, or not, at their current prices. i.e. The ETF is a basket, so look at each thing in the basket. Of course, most people buy ETFs because they don't want to do this kind of analysis and are happy with market average returns. Even so, sector-based ETFs are often used by traders to buy (or sell) entire sectors that may be undervalued (or overvalued)." "Does the bolded sentence apply for ETFs and ETF companies? No, the value of an ETF is determined by an exchange and thus the value of the share is whatever the trading price is. Thus, the price of an ETF may go up or down just like other securities. Money market funds can be a bit different as the mutual fund company will typically step in to avoid ""Breaking the Buck"" that could happen as a failure for that kind of fund. To wit,   must ETF companies invest a dollar in the ETF for every dollar that an   investor deposited in this aforesaid ETF? No, because an ETF is traded as shares on the market, unless you are using the creation/redemption mechanism for the ETF, you are buying and selling shares like most retail investors I'd suspect. If you are using the creation/redemption system then there are baskets of other securities that are being swapped either for shares in the ETF or from shares in the ETF." The main reason I'm aware of that very few individuals do this sort of trading is that you're not taking into account the transaction costs, which can and will be considerable for a small-time investor. Say your transaction costs you $12, that means in order to come out ahead you'll have to have a fairly large position in a given instrument to make that fee back and some money. Most smaller investors wouldn't really want to tie up 5-6 figures for a day on the chance that you'll get $100 back. The economics change for investment firms, especially market makers that get special low fees for being a market maker (ie, offering liquidity by quoting all the time). Why don't you look at the actual funds and etfs in question rather than seeking a general conclusion about all pairs of funds and etfs?  For example, Vanguard's total stock market index fund (VTSAX) and ETF (VTI).  Comparing the two on yahoo finance I find no difference over the last 5 years visually.  For a different pair of funds you may find something very slightly different.   In many cases the index fund and ETF will not have the same benchmark and fees so comparisons get a little more cloudy.  I recall a while ago there was an article that was pointing out that at the time emerging market ETF's had higher fees than corresponding index funds.  For this reason I think you should examine your question on a case-by-case basis.  Index fund and ETF returns are all publicly available so you don't have to guess. Bond ETFs are just another way to buy a bond mutual fund.  An ETF lets you trade mutual fund shares the way you trade stocks, in small share-size increments.  The content of this answer applies equally to both stock and bond funds. If you are intending to buy and hold these securities, your main concerns should be purchase fees and expense ratios.  Different brokerages will charge you different amounts to purchase these securities.  Some brokerages have their own mutual funds for which they charge no trading fees, but they charge trading fees for ETFs.  Brokerage A will let you buy Brokerage A's mutual funds for no trading fee but will charge a fee if you purchase Brokerage B's mutual fund in your Brokerage A account. Some brokerages have multiple classes of the same mutual fund.  For example, Vanguard for many of its mutual funds has an Investor class (minimum $3,000 initial investment), Admiral class (minimum $10,000 initial investment), and an ETF (share price as initial investment).  Investor class has the highest expense ratio (ER).  Admiral class and the ETF generally have much lower ER, usually the same number.  For example, Vanguard's Total Bond Market Index mutual fund has Investor class (symbol VBMFX) with 0.16% ER, Admiral (symbol VBTLX) with 0.06% ER, and ETF (symbol BND) with 0.06% ER (same as Admiral).  See Vanguard ETF/mutual fund comparison page.  Note that you can initially buy Investor class shares with Vanguard and Vanguard will automatically convert them to the lower-ER Admiral class shares when your investment has grown to the Admiral threshold. Choosing your broker and your funds may end up being more important than choosing the form of mutual fund versus ETF.  Some brokers charge very high purchase/redemption fees for mutual funds.  Many brokers have no ETFs that they will trade for free.  Between funds, index funds are passively managed and are just designed to track a certain index; they have lower ERs.  Actively managed funds are run by managers who try to beat the market; they have higher ERs and tend to actually fall below the performance of index funds, a double whammy. See also Vanguard's explanation of mutual funds vs. ETFs at Vanguard. See also Investopedia's explanation of mutual funds vs. ETFs in general. The way it is handled with ETF's is that someone has to gather a block of units and redeem them with the fund. So, with the mutual fund you redeem your unit directly with the fund, always, you never sell to another player. With the ETF - its the opposite, you sell to another player. Once a player has a large chunk of units - he can go to the fund and redeem them. These are very specific players (investment banks), not individual investors.