What happens to an ETF if one of the companies in the ETF gets aquired?
There are a number of ways this can result. In a broad ETF, such as SPY, the S&P 500 spider, the S&P index will have 500 stocks no matter what, so a buyout would simply result in a re-shuffling of the index makeup. No buyout will happen so quickly that there's no time to choose the next stock to join the index. In your case, if the fund manager (per the terms of the prospectus) wishes to simply reallocate the index to remove the taken-over stock that's probably how he handle it.  Unless of course, the prospectus dictates otherwise. In which case, a cash dividend is a possible alternative.
My understanding was that if a company buys back shares then those shares are 'extinguished' I.e. the rest of the shareholders now own a greater portion of the company. However, if there is only one share left, then the company could not buy it because doing so would extinguish it leaving the company without an owner. That result would run contrary to the requirements for an incorporated company in countries like NZ and Australia. ETF is essentially a stock, from accounting perspective. Treat it as just another stock in the portfolio. "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?" The money goes to the seller.  There are a lot of behind the scenes things that happen, and some transactions are very complicated with many parties involved (evidenced by all the comments on @keshlam's perfectly reasonable high-level answer), but ultimately the money goes to the seller.  Sometimes the seller is the company.  The billions of shares that change hands each day are moving between other individuals like you and investment funds; these transactions have no direct impact on the company's financials, in general. You seem to think that stock exchanges are much more than they actually are. But it's right there in the name: stock exchange. It's a place where people exchange (i.e. trade) stocks, no more and no less. All it does is enable the trading (and thereby price finding). Supposedly they went into mysterious bankruptcy then what will happen to the listed companies  Absolutely nothing. They may have to use a different exchange if they're planning an IPO or stock buyback, that's all. and to the shareholder's stock who invested in companies that were listed in these markets ?  Absolutley nothing. It still belongs to them. Trades that were in progress at the moment the exchange went down might be problematic, but usually the shutdown would happen in a manner that takes care of it, and ultimately the trade either went through or it didn't (and you still have the money). It might take some time to establish this. Let's suppose I am an investor and I bought stocks from a listed company in NYSE and NYSE went into bankruptcy, even though NYSE is a unique business, meaning it doesn't have to do anything with that firm which I invested in. How would I know the stock price of that firm  Look at a different stock exchange. There are dozens even within the USA, hundreds internationally. and will I lose my purchased stocks ?  Of course not, they will still be listed as yours at your broker. In general, what will happen after that ?  People will use different stock exchanges, and some of them migth get overloaded from the additional volume. Expect some inconveniences but no huge problems. Absolutely nothing, and it's not their call to make.  The shareholders will want to cut it into as many parts as they  can sell to recoup some of their lost investment. The judge will demand it even if they suddenly had a moral thought.  This will happen when this (and all those other companies) go under, refocuses priorities, or shuts down departments. You would still be the legal owner of the shares, so you would almost certainly need to transfer them to a broker than supports the Hong Kong Stock Exchange (which allows you to trade on the Shanghai exchange). In order to delist they would need to go through a process which would include enabling shareholders to continue to access their holdings. There is no margin call. Inverse ETFs use derivatives that would lose value in the case you describe though this doesn't force a margin call as you may be misunderstanding how these funds are constructed. This is great. Thanks! So, just assuming a fund happened to average out to libor plus 50 for a given year, would applying that rate to the notional value of the index swaps provide a reasonable estimate of the drag an ETF investor would experience due to the cost associated with the index swaps?  For instance, applying this to the hypothetical I linked to in the original question, they assumed fund assets of $100M with 2x leverage achieved through $85M of S&amp;P500 stocks, $25M of S&amp;P500 futures, and a notional value of the S&amp;P500 swaps at $90M. So the true costs to an ETF investor would be: expense ratio + commissions on the $85M of S&amp;P500 holdings + costs associated with $25M of futures contracts + costs associated with the $90M of swaps? And the costs associated with the $90M of swaps might be roughly libor plus 50? Adding to the answers above, there is another source of risk: if one of the companies you are short receives a bid to be purchased by another company, the price will most probably rocket... You can check the website for the company that manages the fund. For example, take the iShares Nasdaq Biotechnology ETF (IBB). iShares publishes the complete list of the fund's holdings on their website. This information isn't always easy to find or available, but it's a place to start. For some index funds, you should just be able to look up the index the fund is trying to match. This won't be perfect (take Vanguard's S&P 500 ETF (VOO); the fund holds 503 stocks, while the S&P 500 index is comprised of exactly 500), but once again, it's a place to start. A few more points to keep in mind. Remember that many ETF's, including equity ETF's, will hold a small portion of their assets in cash or cash-equivalent instruments to assist with rebalancing. For index funds, this may not be reflected in the index itself, and it may not show up in the list of holdings. VOO is an example of this. However, that information is usually available in the fund's prospectus or the fund's site. Also, I doubt that many stock ETF's, at least index funds, change their asset allocations all that frequently. The amounts may change slightly, but depending on the size of their holdings in a given stock, it's unlikely that the fund's manager would drop it entirely. "What will happen if the stock price just continues to decline?  Nothing. What would happen if folks just stop trading it? Nothing. What if the company goes private? Then they will have to buy you out based on some agreed upon price, as voted by the board and (potentially) approved by the shareholders. Depending on the corporation charter, the board may not be required to seek the shareholders' approval, but if the price the board agreed upon is unreasonable you can sue and prevent the transaction. How do they decide the fair value of the outstanding stocks? Through a process called ""valuation"", there are accounting firms which specialize in this area of public accounting." "If anything, the price of an ETF is more tightly coupled to the underlying holdings or assets than a mutual fund, because of the independent creation/destruction mechanism. With a mutual fund, the price is generally set once at the end of each day, and the mutual fund manager has to deal with investments and redemptions at that price. By the time they get to buying or selling the underlying assets, the market may have moved or they may even move the market with those transactions. With an ETF, investment and redemption is handled by independent ""authorized participants"". They can create new units of the ETF by buying up the underlying assets and delivering them to the ETF manager, and vice versa they can cancel units by requesting the underlying assets from the ETF manager. ETFs trade intraday (i.e. at any time during trading hours) and any time the price diverges too far from the underlying assets, one of the authorized participants has an incentive to make a small profit by creating or destroying units of the ETF, also intraday." 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). I'm not a professional, but my understanding is that US funds are not considered PFICs regardless of the fact that they are held in a foreign brokerage account. In addition, be aware that foreign stocks are not considered PFICs (although foreign ETFs may be).