Understanding differences between S&P500 index-tracking ETFs
"Regarding SPY: ""One SPDR unit is valued at approximately 1/10 of the value of the S&P 500. Dividends are distributed quarterly, and are based on the accumulated stock dividends held in trust, less any expenses of the trust.""  (source)  These are depository receipts, not the actual stocks. Regarding IVV: ""The component stocks are weighted according to the total float-adjusted market value of their outstanding shares. The Fund invests in sectors, such as energy, information technology, industrials, financials, consumer staples, healthcare, telecom services, consumer discretionary and materials.""  (more here) VOO is the Vanguard S&P 500 ETF. The tracking error seems pretty small to me.  I went to Google Finance and plotted the percent change for all four on one chart.  They lie pretty much on top of one another.  The actual dollar value of each one doesn't matter nearly as much as the fact that they move up and down almost in lock-step.  There may be a larger difference going farther out, but for three separate financial products, the agreement is still remarkably good." "Back in the olden days, if you wanted to buy the S&P, you had to have a lot of money so you can buy the shares. Then somebody had the bright idea of making a fund that just buys the S&P, and then sells small pieces of it to investor without huge mountains of capital. Enter the ETFs. The guy running the ETF, of course, doesn't do it for free. He skims a little bit of money off the top. This is the ""fee"". The major S&P ETFs all have tiny fees, in the percents of a percent. If you're buying the index, you're probably looking at gains (or losses) to the tune of 5, 10, 20% - unless you're doing something really silly, you wouldn't even notice the fee. As often happens, when one guy starts doing something and making money, there will immediately be copycats. So now we have competing ETFs all providing the same service. You are technically a competitor as well, since you could compete with all these funds by just buying a basket of shares yourself, thereby running your own private fund for yourself. The reason this stuff even started was that people said, ""well why bother with mutual funds when they charge such huge fees and still don't beat the index anyway"", so the index ETFs are supposed to be a low cost alternative to mutual funds. Thus one thing ETFs compete on is fees: You can see how VOO has lower fees than SPY and IVV, in keeping with Vanguard's philosophy of minimal management (and management fees). Incidentally, if you buy the shares directly, you wouldn't charge yourself fees, but you would have to pay commissions on each stock and it would destroy you - another benefit of the ETFs. Moreover, these ETFs claim they track the index, but of course there is no real way to peg an asset to another. So they ensure tracking by keeping a carefully curated portfolio. Of course nobody is perfect, and there's tracking error. You can in theory compare the ETFs in this respect and buy the one with the least tracking error. However they all basically track very closely, again the error is fractions of the percent, if it is a legitimate concern in your books then you're not doing index investing right. The actual prices of each fund may vary, but the price hardly matters - the key metric is does it go up 20% when the index goes up 20%? And they all do. So what do you compare them on? Well, typically companies offer people perks to attract them to their own product. If you are a Fidelity customer, and you buy IVV, they will waive your commission if you hold it for a month. I believe Vanguard will also sell VOO for free. But for instance Fidelity will take commission from VOO trades and vice versa. So, this would be your main factor. Though, then again, you can just make an account on Robinhood and they're all commission free. A second factor is reliability of the operator. Frankly, I doubt any of these operators are at all untrustworthy, and you'd be buying your own broker's ETF anyway, and presumably you already went with the most trustworthy broker. Besides that, like I said, there's trivial matters like fees and tracking error, but you might as well just flip a coin. It doesn't really matter."
The S&P500 is an index, not an investment by itself.  The index lists a large number of stocks, and the value of the index is the price of all the stocks added together. If you want to make an investment that tracks the S&P500, you could buy some shares of each stock in the index, in the same proportions as the index.  This, however, is impractical for just about everyone. Index mutual funds provide an easy way to make this investment.  SPY is an ETF (exchange-traded mutual fund) that does the same thing. An index CFD (contract for difference) is not the same as an index mutual fund.  There are a number of differences between investing in a security fund and investing in a CFD, and CFDs are not available everywhere. After looking at both S&P GSCI Crude Oil Index Excess Return (INDEXSP:SPGSCLP) and CS VS 3x LC ETN NYSEARCA: UWTI they seem to track well (using Google Finance).   I'm not seeing where your statement this ETN loses whether oil is gaining or not holds true.   Both have posted a year-over-year loss. In the past year the Crude Oil index has fallen from a high of 494 on October 6, 2014 to a low of 213 as of today October 5th, 2015.  So of course the UWTI will lose as well. Please also notice that that, as stated in the prospectus for UWTI: The ETNs are intended to be daily trading tools for sophisticated   investors to manage daily trading risks. They are designed t o achieve   their stated investment objectives on a daily basis, but their   performance over different periods of time can differ significantly fr   om their stated daily objectives. The ETNs are riskier than securities   that have intermediate or long-term investment objectives, and may not   be sui table for investors who plan to hold them for a period other   than one day. You might want to look into investing in an ETF for long term investment goals and objectives.  Oil ETF List ETFs are legally separate from their issuer, so the money invested should (the lines can get blurry in a massive crisis) be inaccessible to any bankruptcy claims. The funds assets (its shares in S&P500 companies) are held by a custodian who also keeps these assets separate from their own book. That said, if no other institution takes over the SPY funds the custodian will probably liquidate the fund and distribute the proceeds to the ETF holders, this is likely a less than ideal situation for the holders as the S&P500 would probably not be at its highest levels if State Street is going bankrupt (not to mention the potential taxation). "For whatever it's worth.  Judging from the comments in the other answers, I think everyone is addressing your question, ""How can you possibly lose money,""  there are a lot of ways to possibly lose money in the stock market.  Here are my thoughts.  This is a chart of the S&P 500 from about 1996 to about 2012.  At the top from the first arrow the entire S&P500 index fell about 45%.  From the top of the second arrow the entire S&P500 index fell about 52%.  It is really easy to look at our sustained bull market and feel invincible.  And while I'll concede that not every company in the index fell over these two periods, bear in mind that the S&P500 index is a collection of the 500 largest companies in the United States, and the entire index lost half it's value twice.  As the companies contained in the index shrink in value, they were replaced by companies that are the new biggest 500 in the country, then those fell too, and so on and so forth until the entire index lost half. Value is a funny thing because it isn't necessarily tied to the performance of the business (look at the current rosy valuations of all these non-earnings tech-companies).  It could be that a company is still performing very well but there are just no buyers for the stock.   So, how can you lose money in the stock market?  Very easily.  In A practical sense, it's when you need the money and can no longer weather the storm.  People who went out for retirement around 2000 couldn't sit around and wait until 2007 for their account values to be replenished.  This is why you roll off your stock exposure as you age.  As you get older you don't have time and if you stop having income you can find yourself selling your assets at the least opportune time." +1.  Most ETFs (namely the passive index-tracking ones) will be taking liquidity via market on close orders, since they absolutely need to be filled.  Active ETFs, which may have more discretion, may be able to provide liquidity during the day based on market conditions and get rebates that way. There are a few ETFs that fall into the money market category: SHV, BIL, PVI and MINT.  What normally looks like an insignificant expense ratio looks pretty big when compared to the small yields offered by these funds. The same holds for the spread and transaction fees. For that reason, I'm not sure if the fund route is worth it. To supplement Ben's answer: Following 'smart money' utilizes information available in a transparent marketplace to track the holdings of professionals.  One way may be to learn as much as possible about fund directors and monitor the firms holdings closely via prospectus. I believe certain exchanges provide transaction data by brokers, so it may be possible for a well-informed individual to monitor changes in a firms' holdings in between prospectus updates.  An example of a play on 'smart money':  S&P500 companies are reviewed for weighting and the list changes when companies are dropped or added. As you know there are ETFs and funds that reflect the holdings of the SP500.  Changes to the list trigger  'binary events' where funds open or close a position. Some people try to anticipate the movements of the SP500 before 'smart money' adjusts their positions. I have heard some people define smart money as people who get paid whether their decisions are right or wrong, which in my opinion, best captures the term. This Udemy course may be of interest: https://www.udemy.com/tools-for-trading-investing/ "The S&P 500 is an index. This refers to a specific collection of securities which is held in perfect proportion. The dollar value of an index is scaled arbitrarily and is based off of an arbitrary starting price. (Side note: this is why an index never has a ""split""). Lets look at what assumptions are included in the pricing of an index: All securities are held in perfect proportion. This means that if you invest $100 in the index you will receive 0.2746 shares of IBM, 0.000478 shares of General Motors, etc. Also, if a security is added/dropped from the list, you are immediately rebalancing the remaining money. Zero commissions are charged. When the index is calculated, they are using the current price (last trade) of the underlying securities, they are not actually purchasing them. Therefore it assumes that securities may be purchased without commission or other liquidity costs. Also closely related is the following. The current price has full liquidity. If the last quoted price is $20 for a security, the index assumes that you can purchase an arbitrary amount of the security at that price with a counterparty that is willing to trade. Dividends are distributed immediately. If you own 500 equities, and most distributed dividends quarterly, this means you will receive on average 4 dividends per day. Management is free. All equities can be purchased with zero research and administrative costs. There is no gains tax. Trading required by the assumptions above would change your holdings constantly and you are exempt from short-term or long-term capital gains taxes. Each one of these assumptions is, of course, invalid. And the fund which endeavors to track the index must make several decisions in how to closely track the index while avoiding the problems (costs) caused by the assumptions. These are shortcuts or ""approximations"". Each shortcut leads to performance which does not exactly match the index. Management fees. Fees are charged to the investor as load, annual fees and/or redemptions. Securities are purchased at real prices. If Facebook were removed from the S&P 500 overnight tonight, the fund would sell its shares at the price buyers are bidding the next market day at 09:30. This could be significantly different than the price today, which the index records. Securities are purchased in blocks. Rather than buying 0.000478 shares of General Motors each time someone invests a dollar, they wait for a few people and then buy a full share or a round lot. Securities are substituted. With lots of analysis, it may be determined that two stocks move in tandem. The fund may purchase two shares of General Motors rather than one of General Motors and Ford. This halves transaction costs. Debt is used. As part of substitution, equities may be replaced by options. Option pricing shows that ownership of options is equivalent to holding an amount of debt. Other forms of leverage may also be employed to achieve desired market exposure. See also: beta.  Dividends are bundled. VFINX, the largest S&P 500 tracking fund, pays dividends quarterly rather than immediately as earned. The dividend money which is not paid to you is either deployed to buy other securities or put into a sinking fund for payment. There are many reasons why you can't get the actual performance quoted in an index. And for other more exotic indices, like VIX the volatility index, even more so. The best you can do is work with someone that has a good reputation and measure their performance."