How to understand a volatility based ETF like VXX
"The VIX is a mathematical aggregate of the implied volatilities of the S&P 500 Index components. It itself cannot be traded as there currently is no way to only hold a position on an implied volatility alone.  Implied volatility can only currently be derived from an option relative to its underlying.  Further, the S&P 500 index itself cannot be traded only the attempts to replicate it.  For assets that are not tradable, derivatives can be ""cash settled"" where the value of the underlying is delivered in cash.  Cash settlement can be used for underlyings that in fact due trade but are frequently only elected if the underlying is costly to deliver or there is an incentive to circumvent regulation. Currently, only futures that settle on the value of the VIX at the time of delivery trade; in other words, VIX futures holders must deliver on the value of the VIX in cash upon settlement.  Options in turn trade on those futures and in turn are also cash settled on the value of the underlying future at expiration. The VXX ETF holds one to two month VIX futures that it trades out of before delivery, so while it is impossible to know exactly what is held in the VXX accounts unless if one had information from an insider or the VXX published such details, one can assume that it holds VIX futures contracts no later than two settlements from the preset.  It should be noted that the VXX does not track the VIX over the long run because of the cost to roll the futures and that the futures are more stable than the VIX, so it is a poor substitute for the VIX over time periods longer than one day. ""Underlying"" now implies any abstract from which a financial product derives its value." "To understand the VXX ETF, you need to understand VIX futures, to understand VIX futures you need to understand VIX, to understand VIX you need to understand options pricing formulas such as the ""Black Scholes"" formula Those are your prerequisites. Learn at your own pace. Short Answer: When you buy VXX you are buying the underlying are front month VIX futures. Limited by the supply of the ETF's NAV (Net Asset Value) units. It is assumed that the ETF manager is actually buying and selling more VIX front month futures to back the underlying ETF. Long Answer: Assume nobody knows what an options contract should be worth. Therefore formulas have been devised to standardize how to price an options contract. The Black-Scholes formula is widely used, one of the variables in this formula is ""Implied Volatility"", which basically accounts for the mispricing of options when the other variables (Intrinsic Value, delta, gamma, theta...) don't completely explain how much the option is worth. People are willing to pay more for options when the perception is that they will be more profitable, ""implied volatility"" tracks these changes in an option's demand, where the rest of the black-scholes formula creates a price for an option that will always be the same. Each stock in the market that also trades standardized options will have implied volatility which can be computed from the price of those options. The ""Volatility Index"" (VIX), looks at the implied volatility of MANY STOCK's options contracts. Specifically the ""implied volatility of out the money puts on the S&P 500"". If you don't know what that quoted part of the sentence means, then you have at least five other individual questions to ask before you re-read this answer and understand the relevance of these followup questions: Why would people buy out-the-money puts on the S&P 500? Why would people pay more for out-the-money puts on the S&P 500 on some days and pay less for them on other days? This is really the key to the whole puzzle. Anyway, now that we have this data, people wanted to speculate on the future value of the VIX. So VIX futures contracts began trading and with it there came a liquid market. There doesn't need to be anything physical to back a financial product anymore. A lot of people don't trade futures, retail investors have practically only heard of ""the stock market"". So one investment bank decided to make a fund that only holds VIX futures that expire within a month. (front month futures). They split that fund up into shares and listed it on the stock market, like alchemy the VXX was formed. Volatility studies are fascinating, and get way more complex than this now that the VXX ETF also has liquid options contracts trading on it too, and there are leveraged VIX ETF funds that also trade options"
"I'm trying to understand how an ETF manager optimized it's own revenue.  Here's an example that I'm trying to figure out.  ETF firm has an agreement with GS for blocks of IBM. They have agreed on daily VWAP + 1% for execution price.  Further, there is a commission schedule for 5 mils with GS. Come month end, ETF firm has to do a monthly rebalance. As such must buy 100,000 shares at IBM which goes for about $100 The commission for the trade is 100,000 * 5 mils = $500 in commission for that trade. I assume all of this is covered in the expense ratio. Such that if VWAP for the day was 100, then each share got executed to the ETF at 101 (VWAP+ %1) + .0005 (5 mils per share) = for a resultant 101.0005 cost basis  The ETF then turns around and takes out (let's say) 1% as the expense ratio ($1.01005 per share)  I think everything so far is pretty straight forward. Let me know if I missed something to this point.  Now, this is what I'm trying to get my head around. ETF firm has a revenue sharing agreement as well as other ""relations"" with GS. One of which is 50% back on commissions as soft dollars. On top of that GS has a program where if you do a set amount of ""VWAP +"" trades you are eligible for their corporate well-being programs and other ""sponsorship"" of ETF's interests including  helping to pay for marketing, rent, computers, etc.  Does that happen? Do these disclosures exist somewhere?" "Certainly no one knows in advance how much a stock is going to swing around. However, there are measures of how much it has swung around in the past, and there are people who will estimate the probability. First of all, there's a measure of an individual stock's volatility, commonly referred to as ""beta"". A stock with a beta of 1 tends to rise and fall about as much as the market at large. A stock with a beta of 2, in the meantime, would rise 10% when the market is up 5%. These are, of course, historical averages. See Wikipedia: http://en.wikipedia.org/wiki/Beta_(finance) Secondly, you can get an implied measure of volatility expectations by looking at options pricing. If a stock is particularly volatile, the chance of a big price move will be baked into the price of the stock options. (Note also that other things affect options pricing, such as the time value of money.) For an options-based measure of the volatility of the whole market, see the Volatility Index aka the ""Fear Gauge"", VIX.  Wikipedia: http://en.wikipedia.org/wiki/VIX Chart: http://finance.yahoo.com/q?s=%5EVIX Looking at individual stocks as a group (and there's an oxymoron for you), individual stocks are definitely much more likely to have big moves than the market. Besides Netflix, consider the BP oil spill, or the Tokyo Electric Power Company's Fukushima incident (yow!). I don't have any detailed statistics on quantitatively how much, mind you, but in application, a standard piece of advice says not to put more than 5% of your portfolio in a single company's stock. Diversification protects you. (Alternatively, if you're trying to play Mr. Sophisticated Stock-Picker instead of just buying an index fund, you can also buy insurance through stock options: hedging your bets. Naturally, this will eat up part of your returns if your pick was a good one)." The only way to hedge a position is to take on a countervailing position with a higher multiplier as any counter position such as a 1:1 inverse ETF will merely cancel out the ETF it is meant to hedge yielding a negative return roughly in the amount of fees & slippage. For true risk-aversion, continually selling the shortest term available covered calls is the only free lunch.  A suboptimal version, the CBOE BuyWrite Index, has outperformed its underlying with lower volatility. The second best way is to continually hedge positions with long puts, but this can become very tax-complicated since the hedged positions need to be rebalanced continually and expensive depending on option liquidity. The ideal, assuming no taxes and infinite liquidity, is to sell covered calls when implied volatility is high and buy puts when implied volatility is low. Can they change the weights? Yes. Will they? It depends. are ETF's fixed from their inception to their de-listing? It's actually not possible for weights to be fixed, since different assets have different returns. So the weights are constantly changing as long as the market is moving. Usually after a certain period or a substantial market move, fund managers would rebalance and bring the weights back to a certain target. The target weights - what your question is really about - aren't necessarily the same as the initial weights, but often times they are. It depends on the objective of the ETF (which is stated in prospectus). In your example, if the manager drops the weight of the most volatile one, the returns of the ETF and the 5 stocks could be substantially different in the next period. This is not desirable when the ETFs objective is to track performance of those 5 stocks.  Most if not all ETFs are passively-managed. The managers don't get paid for active management. So they don't have incentive to adjust the weights if their funds are tracking the benchmarks just fine. I think that assuming that you're not looking to trade the fund, an index Mutual Fund is a better overall value than an ETF. The cost difference is negligible, and the ability to dollar-cost average future contributions with no transaction costs. You also have to be careful with ETFs; the spreads are wide on a low-volume fund and some ETFs are going more exotic things that can burn a novice investor. Track two similar funds (say Vanguard Total Stock Market: VTSMX and Vanguard Total Stock Market ETF: VTI), you'll see that they track similarly.  If you are a more sophisticated investor, ETFs give you the ability to use options to hedge against declines in value without having to incur capital gains from the sale of the fund. (ie. 20 years from now, can use puts to make up for short-term losses instead of selling shares to avoid losses)  For most retail investors, I think you really need to justify using ETFs versus mutual funds. If anything, the limitations of mutual funds (no intra-day trading, no options, etc) discourage speculative behavior that is ultimately not in your best interest. EDIT: Since this answer was written, many brokers have begun offering a suite of ETFs with no transaction fees. That may push the cost equation over to support Index ETFs over Index Mutual Funds, particularly if it's a big ETF with narrow spreads.. "I thought the other answers had some good aspect but also some things that might not be completely correct, so I'll take a shot. As noted by others, there are three different types of entities in your question:  The ETF SPY, the index SPX, and options contracts. First, let's deal with the options contracts.  You can buy options on the ETF SPY or marked to the index SPX.  Either way, options are about the price of the ETF / index at some future date, so the local min and max of the ""underlying"" symbol generally will not coincide with the min and max of the options.  Of course, the closer the expiration date on the option, the more closely the option price tracks its underlying directly.  Beyond the difference in how they are priced, the options market has different liquidity, and so it may not be able to track quick moves in the underlying. (Although there's a reasonably robust market for option on SPY and SPX specifically.) Second, let's ask what forces really make SPY and SPX move together as much as they do.  It's one thing to say ""SPY is tied to SPX,"" but how?  There are several answers to this, but I'll argue that the most important factor is that there's a notion of ""authorized participants"" who are players in the market who can ""create"" shares of SPY at will.  They do this by accumulating stock in the constituent companies and turning them into the market maker.  There's also the corresponding notion of ""redemption"" by which an authorized participant will turn in a share of SPY to get stock in the constituent companies. (See http://www.spdrsmobile.com/content/how-etfs-are-created-and-redeemed and http://www.etf.com/etf-education-center/7540-what-is-the-etf-creationredemption-mechanism.html) Meanwhile, SPX is just computed from the prices of the constituent companies, so it's got no market forces directly on it.  It just reflects what the prices of the companies in the index are doing. (Of course those companies are subject to market forces.) Key point: Creation / redemption is the real driver for keeping the price aligned.  If it gets too far out of line, then it creates an arbitrage opportunity for an authorized participant.  If the price of SPY gets ""too high"" compared to SPX (and therefore the constituent stocks), an authorized participant can simultaneously sell short SPY shares and buy the constituent companies' stocks.  They can then use the redemption process to close their position at no risk.  And vice versa if SPY gets ""too low."" Now that we understand why they move together, why don't they move together perfectly.  To some extent information about fees, slight differences in composition between SPY and SPX over time, etc. do play.  The bigger reasons are probably that (a) there are not a lot of authorized participants, (b) there are a relatively large number of companies represented in SPY, so there's some actual cost and risk involved in trying to quickly buy/sell the full set to capture the theoretical arbitrage that I described, and (c) redemption / creation units only come in pretty big blocks, which complicates the issues under point b. You asked about dividends, so let me comment briefly on that too.  The dividend on SPY is (more or less) passing on the dividends from the constituent companies. (I think - not completely sure - that the market maker deducts its fees from this cash, so it's not a direct pass through.)  But each company pays on its own schedule and SPY does not make a payment every time, so it's holding a corresponding amount of cash between its dividend payments.  This is factored into the price through the creation / redemption process.  I don't know how big of a factor it is though." I don't think you are missing much, if anything, Brendan. You get massive diversification and low fees with a fund like VTI. I'm not sure if it is good to have everything with only one broker though. I would add to the conversation that the goal shouldn't be to have a giant pile of money in x years..and then spend it down in retirement. A much better/safer goal is to have enough dividends being generated that you never have to touch your capital. Looks like you are starting young so congrats. The Creation/Redemption mechanism is how shares of an ETF are created or redeemed as needed and thus is where there can be differences in what the value of the holdings can be versus the trading price. If the ETF is thinly traded, then the difference could be big as more volume would be where the mechanism could kick in as generally there are blocks required so the mechanism usually created or redeemed in lots of 50,000 shares I believe. From the link where AP=Authorized Participant: With ETFs, APs do most of the buying and selling. When APs sense   demand for additional shares of an ETF—which manifests itself when the   ETF share price trades at a premium to its NAV—they go into the market   and create new shares. When the APs sense demand from investors   looking to redeem—which manifests itself when the ETF share price   trades at a discount—they process redemptions. So, suppose the NAV of the ETF is $20/share and the trading price is $30/share. The AP can buy the underlying securities for $20/share in a bulk order that equates to 50,000 shares of the ETF and exchange the underlying shares for new shares in the ETF. Then the AP can turn around and sell those new ETF shares for $30/share and pocket the gain. If you switch the prices around, the AP would then take the ETF shares and exchange them for the underlying securities in the same way and make a profit on the difference. SEC also notes this same process.