How is an ETF's NAV determined?
An ETF manager will only allow certain financial organisations to create and redeem ETF shares.  These are called Authorised Participants (APs).  The APs have the resources to bundled up packages of shares that they already own and hold in order to match the ETFs requirements.  In the case of the EDEN ETF, this portfolio is the MSCI Denmark Index.  Only APs transact business directly with the ETF manager.   When ETF shares need to be created, the AP will bundle up the portfolio of shares and deliver them to the ETF manager.  In return, the ETF manager will deliver to the AP the corresponding number of shares in the ETF.  Note that no cash changes hands here. (These ETF shares are now available for trading in the market via the AP.  Note that investors do not transact business directly with the ETF manager.) Similarly, when ETF shares need to be redeemed, the AP will deliver the ETF shares to the ETF manager.  In return, the ETF manager will deliver to the AP the corresponding portfolio of shares.  Again, no cash changes hands here. Normally, with an established and liquid ETF, investors like you and me will transact small purchases and sales of ETF shares with other small investors in the market.  In the event that an AP needs to transact business with an  investor, they will do so by either buying or selling the ETF shares.  In the event that they have insufficient ETF shares to meet demand, they will bundle up a portfolio deliver them to the ETF provider in return for ETF shares, thus enabling them to meet demand.  In the event that a lot of investors are selling and the AP ends up holding an excessive amount of ETF shares, they will deliver unwanted shares to the ETF manager in exchange for a portfolio of the underlying shares. According to this scheme, large liquidations of ETF holdings should not effect the share prices of the underlying portfolio.  This is because the underlying shares are not sold in the market, rather they are simply returned to the AP in exchange for the ETF shares (Recall that no cash is changing hands in this type of transaction).   The corresponding trail of dividends and distributions to ETF share holders follows the same scheme.
Investopedia laid out the general information of tax treatment on the ETF fund structures as well as their underlying asset classes: http://www.investopedia.com/financial-edge/0213/how-tax-treatments-of-etfs-work.aspx A general mutual fund's exact holdings are not known on a day-to-day basis, and so technical tools must work with inexact data. Furthermore, the mutual fund shares' NAV depends on lots of different shares that it holds, and the  results of the kinds of analyses that one can do for a single stock must be commingled to produce something analogous for the fund's NAV. In other words, there is plenty of shooting in the dark going on. That being said, there are plenty of  people who claim to do such analyses and will gladly sell you their results (actually, Buy, Hold, Sell recommendations) for whole fund families (e.g. Vanguard) in the form of a monthly or weekly Newsletter delivered by US Mail (in the old days) or electronically (nowadays). Some people who subscribe to such newsletters swear by them, while others swear at them and don't renew their subscriptions; YMMV. "What you seem to want is a dividend reinvestment plan (DRIP).  That's typically offered by the broker, not by the ETF itself.  Essentially this is a discounted purchase of new shares when you're dividend comes out.  As noted in the answer by JoeTaxpayer, you'll still need to pay tax on the dividend, but that probably won't be a big problem unless you've got a lot of dividends.  You'll pay that out of some other funds when it's due.  All DRIPs (not just for ETFs) have potential to complicate computation of your tax basis for eventual sale, so be aware of that.  It doesn't have to be a show-stopper for you, but it's something to consider before you start.  It's probably less of a problem now than it used to be since brokers now have to report your basis on the 1099-B in the year of sale, reducing your administrative burden (if you trust them to get it right). Here's a list of brokerages that were offering this from a top-of-the-search-list article that I found online: Some brokerages, including TD Ameritrade, Vanguard, Scottrade, Schwab and, to a lesser extent, Etrade, offer ETF DRIPs—no-cost dividend reinvestment programs. This is very helpful for busy clients. Other brokerages, such as Fidelity, leave ETF dividend reinvestment to their clients. Source: http://www.etf.com/sections/blog/23595-your-etf-has-drip-drag.html?nopaging=1 Presumably the list is not constant.  I almost didn't included but I thought the wide availability (at least as of the time of the article's posting) was more interesting than any specific broker on it. You'll want to do some research before you choose a broker to do this.  Compare fees for sure, but also take into account other factors like how soon after the dividend they do the purchase (is it the ex-date, the pay date, or something else?).  A quick search online should net you several decent articles with more information.  I just searched on ""ETF DRIP"" to check it out." "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" "My knowledge relates to ETFs only. By definition, an ETF's total assets can increase or decrease based upon how many shares are issued or redeemed.  If somebody sells shares back to the ETF provider (rather than somebody else on market) then the underlying assets need to be sold, and vice-versa for purchasing from the ETF provider.  ETFs also allow redemptions too in addition to this. For an ETF, to determine its total assets, you need to you need to analyze the Total Shares on Issue multipled by the Net Asset Value.  ETFs are required to report shares outstanding and NAV on a daily basis. ""Total assets"" is probably more a function of marketing rather than ""demand"" and this is why most funds report on a net-asset-value-per-share basis. Some sites report on ""Net Inflows"" is basically the net change in shares outstanding multiplied by the ETF price. If you want to see this plotted over time you can use a such as: http://www.etf.com/etfanalytics/etf-fund-flows-tool which allows you to see this as a ""net flows"" on a date range basis." Quick and dirty paper but pretty interesting.. I'm not in Portfolio Management but I probably would have ended up at the modal number as well.   I don't know the subject deeply enough to answer my own question, but is the bias always toward underestimation of variance? Or is that a complex of the way the problem was set up?   Another question I have for those in investment management; Would this impact asset allocation? You could look up the P/E of an equivalent ETF, or break the ETF into components and look those up. Each index has its own methodology, usually weighted by market cap.  See here: http://www.amex.com/etf/prodInf/EtAllhold.jsp?Product_Symbol=DIA The process would look something like:  1. Register your investment company with the SEC 2. Get the ETF approved by the SEC  3. Get a custodian bank (likely requires min assets of a few million) 4. Get listed on an exchange like NYSEARCA by meeting requirements and have an IPO   1 and 2 probably require a lot of time and fees and would be wise to have a lawyer advising, 3 is obviously difficult due to asset requirements and 4 would probably involve an investment bank plus more fees