Why are index funds called index funds?
"Because they track an index. Edited: The definition of the word in this case meaning ""something used or serving to point out; a sign, token, or indication"" from Meaning  #3 I presume therefore you are asking what an index is? There are many variations of what makes up an Index but in short it is a representation of some part of a market. An extremely simplistic calculation would be to take a basket of stocks, and sum their prices.  If one stock moves up a dollar, and one moves down a dollar, the index has effectively not changed, as it is presumed that the loss in one is offset by the gain in the other."
ACWI refers to a fund that tracks the MSCI All Country World Index, which is  A market capitalization weighted index designed to provide a broad measure of equity-market performance throughout the world. The MSCI ACWI is maintained by Morgan Stanley Capital International, and is comprised of stocks from both developed and emerging markets.  The ex-US in the name implies exactly what it sounds; this fund probably invests in stock markets (or stock market indexes) of the countries in the index, except the US. Brd Mkt refers to a Broad Market index, which, in the US, means that the fund attempts to track the performance of a wide swath of the US stock market (wider than just the S&P 500, for example). The Dow Jones U.S. Total Stock Market Index, the Wilshire 5000 index, the Russell 2000 index, the MSCI US Broad Market Index, and the CRSP US Total Market Index are all examples of such an index. This could also refer to a fund similar to the one above in that it tracks a broad swath of the several stock markets across the world. I spoke with BNY Mellon about the rest, and they told me this: EB - Employee Benefit (a bank collective fund for ERISA qualified assets) DL - Daily Liquid (provides for daily trading of fund shares) SL - Securities Lending (fund engages in the BNY Mellon securities lending program) Non-SL - Non-Securities Lending (fund does not engage in the BNY Mellon securities lending program) I'll add more detail. EB (Employee Benefit) refers to plans that fall under the Employee Retirement Income Security Act, which are a set a laws that govern employee pensions and retirement plans. This is simply BNY Mellon's designation for funds that are offered through 401(k)'s and other retirement vehicles. As I said before, DL refers to Daily Liquidity, which means that you can buy into and sell out of the fund on a daily basis. There may be fees for this in your plan, however. SL (Securities Lending) often refers to institutional funds that loan out their long positions to investment banks or brokers so that the clients of those banks/brokerages can sell the shares short. This SeekingAlpha article has a good explanation of how this procedure works in practice for ETF's, and the procedure is identical for mutual funds: An exchange-traded fund lends out shares of its holdings to another party and charges a rental fee. Running a securities-lending program is another way for an ETF provider to wring more return out of a fund's holdings. Revenue from these programs is used to offset a fund's expenses, which allows the provider to charge a lower expense ratio and/or tighten the performance gap between an ETF and its benchmark. "To add on to the other answers, in asking why funds have different price points one might be asking why stocks aren't normalized so a unit price of $196 in one stock can be directly compared to the same price in another stock.  While this might not make sense with AAPL vs. GOOG (it would be like comparing apples to oranges, pun intended, not to mention how would two different companies ever come to such an agreement) it does seem like it would make more sense when tracking an index.  And in fact less agreement between different funds would be required as some ""natural"" price points exist such as dividing by 100 (like some S&P funds do). However, there are a couple of reasons why two different funds might price their shares of the same underlying index differently. Demand - If there are a lot of people wanting the issue, more shares might be issued at a lower price.  Or, there might be a lot of demand centered on a certain price range. Pricing - shares that are priced higher will find fewer buyers, because it makes it harder to buy round lots (100 shares at $100/share is $10,000 while at $10/share it's only $1000).  While not everyone buys stock in lots, it's important if you do anything with (standardized) options on the stock because they are always acting on lots.  In addition, even if you don't buy round lots a higher price makes it harder to buy in for a specific amount because each unit share has a greater chance to be further away from your target amount. Conversely, shares that are priced too low will also find fewer buyers, because some holders have minimum price requirements due to low price (e.g. penny) stocks tending to be more speculative and volatile. So, different funds tracking the same index might pick different price points to satisfy demand that is not being filled by other funds selling at a different price point." The shift to trading at the close began in 2008. Traders did not want to be caught off guard by surprise news and there was a lot of volatility during the financial crisis, so they would close their position in the evening. Thats how it began. There are two reasons why it sticks around. First, there has been an increase usage of index funds or passive funds. These funds tend to update their positions at the end of the day. From the WSJ: Another factor behind the shift has been the proliferation of passively managed investments, such as index funds. These funds aim to mimic an index, like the S&P 500, by owning the shares that comprise it. Index funds don’t trade as often as active investors, but when they do, it is typically near the market close, traders say. That is because buying or selling a stock at its closing price better aligns their performance with the index they are trying to emulate. The second reason is simply that volume attracts volume. As a result of whats mentioned above, you have a shift to end of day trading, and the corrolary to that is that there is a liquidity shortage from 10am to 3pm. Thus, if you want to buy or sell a stock, but there are few buyers or sellers around, you will significant move the price when you enter your order. Obviously this does not affect retail traders, but imagine hedge funds entering or closing a billion dollar position. It can make a huge impact on price. And one way to mitigate that is to wait until there are more market participants to take the other end of your trade, just as at the end of the day. So this is a self-reinforcing trend that has begun in the markets and will likely stick around. http://www.wsj.com/articles/traders-pile-in-at-the-close-1432768080 "From http://blog.ometer.com/2008/03/27/index-funds/ , Lots of sensible advisers will tell you to buy index funds, but   importantly, the advice is not simply ""buy index funds.""   There are at least two other critical details: 1) asset allocation   across multiple well-chosen indexes, maintained through regular   rebalancing, and 2) dollar cost averaging (or,   much-more-complex-but-probably-slightly-better, value averaging). The   advice is not to take your single lump sum and buy and hold a   cap-weighted index forever. The advice is an investment   discipline which involves action over time, and an initial   choice among indexes. An index-fund-based   strategy is not completely passive, it involves some active risk   control through rebalancing and averaging. If you'd held a balanced portfolio over the last ten years and rebalanced, and even better if you'd dollar cost averaged, you'd have done fine. Your reaction to the last 10 years incidentally is why I don't believe an almost-all-stocks allocation makes sense for most people even if they're pretty young. More detail in this answer: How would bonds fare if interest rates rose? I think some index fund advocacy and books do people a disservice by focusing too much on the extra cost of active management and why index funds are a good deal.  That point is true, but for most investors, asset allocation, rebalancing, and ""autopilotness"" of their setup are more important to outcome than the expense ratio." This is probably the best, most concise and yet detailed answer to this oft-posed question I've seen on this sub. Have an upvote. Only thing I'd add is that HFs' comparatively more active approach creates a moat vs. mutual funds, which are seen as more long-term, passive investments. This means they can charge fees and have higher expense ratios (though obviously anyone in finance who has been conscious in the last five years knows that this is changing) As Ross says, SPX is the index itself. This carries no overheads. It is defined as a capitalization-weighted mixture of the stocks of (about) 500 companies. SPY is an index fund that tries to match the performance of SPX. As an index fund it has several differences from the index: "In the case of mutual funds, Net Asset Value (NAV) is the price used to buy and sell shares. NAV is just the value of the underlying assets (which are in turn valued by their underlying holdings and future earnings). So if a fund hands out a billion dollars, it stands to reason their NAV*shares (market cap?) is a billion dollars less. Shareholder's net worth is equal in either scenario, but after the dividend is paid they are more liquid. For people who need investment income to live on, dividends are a cheap way to hold stocks and get regular payments, versus having to sell part of your portfolio every month.  But for people who want to hold their investment in the market for a long long time, dividends only increase the rate at which you have to buy. For mutual funds this isn't a problem: you buy the funds and tell them to reinvest for free. So because of that, it's a prohibited practice to ""sell"" dividends to clients." Many mutual funds include such mechanisms. However, the higher fees for those funds (when compared to simple index funds) may cancel out any improvement the hedging strategy offers.