Why don't SPY, SPX, and the e-mini s&p 500 track perfectly with each other?
"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." 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: "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." As a futures trader, I can tell you that the highs and lows for the ES futures diverge simply because they trade around the clock, from 6PM ET to 5PM ET the next day. The SPX is only open during market hours, as is the SPY, but the SPY also trades in the extended hours sessions for about 3.5 hours before and after the regular hours of 930 AM ET to 4PM ET ET. So bottom line, while they pretty much track each other, the difference in their trading hours results in the highs and lows being different. What you should compare is SPX, SPY NAV, and ES fair value.   Like others have said is SPX is the index that others attempt to track. SPY tracks it, but it can get a tiny bit out of line as explained here by @Brick .  That's why they publish NAV or net asset value.  It's what the price should be.  For SPY this will be very close because of all the participants.  The MER is a factor, but more important is something called tracking error, which takes into account MER plus things like trading expenses plus revenue from securities lending.  SPY (the few times I've checked) has a smaller tracking error than the MER.  It's not much of a factor in pricing differences. ES is the price you'll pay today to get SPX delivered in the future (but settled in cash).  You have to take into account dividends and interest, this is called fair value.  You can find this usually every morning so you can compare what the futures are saying about the underlying index. http://www.cnbc.com/pre-markets/ The most likely difference is you're looking at different times of the day or different open/close calculations.
"Following comments to your question here, you posted a separate question about why SPY, SPX, and the options contract don't move perfectly together.  That's here Why don't SPY, SPX, and the e-mini s&p 500 track perfectly with each other? I provided an answer to that question and will build on it to answer what I think you're asking on this question.  Specifically, I explained what it means that these are ""all based on the S&P.""  Each is a different entity, and different market forces keep them aligned.  I think talking about ""technicals"" on options contracts is going to be too confusing since they are really a very different beast based on forward pricing models, so, for this question, I'll focus on only SPY and SPX. As in my other answer, it's only through specific market forces (the creation / redemption mechanism that I described in my other answer), that they track at all.  There's nothing automatic about this and it has nothing to do with some issuer of SPY actually holding stock in the companies that comprise the SPX index. (That's not to say that the company does or doesn't hold, just that this doesn't drive the prices.)  What ever technical signals you're tracking, will reflect all of the market forces at play.  For SPX (the index), that means some aggregate behavior of the component companies, computed in a ""mathematically pure"" way.  For SPY (the ETF), that means (a) the behavior of SPX and (b) the behavior of the ETF as it trades on the market, and (c) the action of the authorized participants.  These are simply different things. Which one is ""right""?  That depends on what you want to do.  In theory you might be able to do some analysis of technical signals on SPY and SPX and, for example, use that to make money on the way that they fail to track each other.  If you figure out how to do that, though, don't post it here.  Send it to me directly. :)" This article is so dumb. Passive investors should be concerned about poor corporate governance just as much as anyone else. The whole point is that active investors are more hesitant to put their money into companies like snap. Inclusion into an index could lead to technical buying. By ensuring the bare minimum standard in terms of corporate governance, S&amp;P is actually protecting passive investors. In your other question about these funds you quoted two very different yields for them. That pretty clearly says they are NOT tracking the same index. "There was a time when everyone felt their goal was to beat the respective index they followed. But of course, in aggregate, that's a mathematical impossibility. The result was that the average say large cap fund, whose benchmark index would be the S&P, would lag on average by 1-2%.  A trend toward ETFs that would match the market had begun, and the current ETFs that follow the S&P are sub .1% expense.  For the fact that studies (Google ""Dalbar"" for examples) show the typical investor lags not by 1% or 2%, but by far more for reasons of bad timing, my own statement that ""I've gotten a return these past years of .06% less than the S&P"" would have been seen many years ago as failure, now it's bragging. It handily beats the typical investor and yet, can be had by anyone wishing to stay the course, keep the ETF very long term." "I mean, I'd say ""no shit"". The model is easy to reproduce (see the inverse model proposed by CHX and the new NYSE American), and people don't have a real incentive to trade there. IEX's main selling point to the buy side was the reduced price impact order router, which ultimately went away when they became an exchange.  Listings could be interesting, but I can't see why any company that doesn't have some sort of statement to make would want to list there versus the big two, or BATS. Hell, even BATS, a much more established market, has had a hard time drawing listings.  I'm glad they've seen a small bump in market share in the last few months, but I can't see them becoming one of the big three players any time soon (especially after having shat all over the industry during their launch period).  Side note: The UTP SIP (and soon the CTA SIP) are both **much** faster than when IEX went live. Turns out inside updates via the SIP are received faster than the prop market data feed, and faster than updates received over an order entry connection. Under these circumstances the street knows a trade occurred before the participants in the trade. This information asymmetry often results in market makers getting run the hell over, and makes them less likely to quote at the inside on your market." An index will drop a company for several reasons:  A fund decides how close they want to mirror the index. Some do so exactly, others only approximate the index. "Note that an index fund may not be able to precisely mirror the index it's tracking. If enough many people invest enough money into funds based on that index, there may not always be sufficient shares available of every stock included in the index for the fund to both accept additional investment and track the index precisely.  This is one of the places where the details of one index fund may differ from another even when they're following the same index. IDEALLY they ought to deliver the same returns, but in practical terms they're going to diverge a bit. (Personally, as long as I'm getting ""market rate of return"" or better on average across all my funds, at a risk I'm comfortable with, I honestly don't care enough to try to optimize it further. Pick a distribution based on some stochastic modelling tools, rebalance periodically to maintain that distribution, and otherwise ignore it. That's very much to the taste of someone like me who wants the savings to work for him rather than vice versa.)" I've looked into Thinkorswim; my father uses it. Although better than eTrade, it wasn't quite what I was looking for. Interactive Brokers is a name I had heard a long time ago but forgotten. Thank you for that, it seems to be just what I need. I'm not exactly sure, but it may be due to liquidity preference.  SPY has a much higher volume (30d average of roughly 70m vs. 3.3m, 1.9m for IVV, VOO respectively), and similarly has a narrow bid ask spread of about 0.01 compared to 0.02 for the other two.  I could be wrong, but I'm going to leave this post up and look in to it later, I'm curious too. The difference is very consistent though, so it may be something in their methodology. Both of these are futures contracts on the Ibovespa Brasil Sao Paulo Stock Exchange Index; the mini being exactly that, a mini version (or portion) of the regular futures contract. The mini counterpart makes trading the index more affordable to individual investors and hence increase liquidity. I use two different brokerages, both well-known. I got a bit spooked during the financial crisis and didn't want to have all my eggs in one basket. The SIPC limits weren't so much a factor. At the time, I was more worried about the hassle of dealing with a Lehman-style meltdown. If one were to fail, the misery of waiting and filing and dealing with SIPC claims would be mitigated by having half of my money in another brokerage. In hindsight, I was perhaps a bit too paranoid. Dealing with two separate brokerages is not much of an inconvenience, though, and it's interesting to see how their web interfaces are slightly different and some things are easier to do with one vs the other. Overall, they're really similar and I can't say there's much advantage (other than my tin-foil hat tendencies) to splitting it up like that. "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." I don't see it in any of the exchange feeds I've gone through, including the SIPs. Not sure if there's something wrong with Nasdaq Last Sale (I don't have that feed) but it should be putting out the exact same data as ITCH. "Switching to only 401k or only SPY?  Both bad ideas.  Read on. You need multiple savings vehicles.  401k, Roth IRA, emergency fund.  You can/should add others for long term savings goals and wealth building.  Though you could combine the non-tax-advantaged accounts and keep track of your minimum (representing the emergency fund). SPY is ETF version of SPDR index mutual fund tracking the S&P 500 index.  Index funds buy weighted amounts of members of their index by an algorithm to ensure that the total holdings of the fund model the index that they track.  They use market capitalization and share prices and other factors to automatically rebalance.   Individual investors do not directly affect the composition or makeup of the S&P500, at least not visibly.  Technically, very large trades might have a visible effect on the index makeup, but I suspect the size of the trade would be in the billions.   An Electronically Traded Fund is sold by the share and represents one equal share of the underlying fund, as divided equally amongst all the shareholders.  You put dollars into a fund, you buy shares of an ETF. In the case of an index ETF, it allows you to ""buy"" a fractional share of the underlying index such as the S&P 500. For SPY, 10 SPY shares represent one S&P basket.  Targeted retirement plan funds combine asset allocation into one fund.  They are a one stop shop for a diversified allocation.  Beware the fees though.  Always beware the fees. Fidelity offers a huge assortment of plans.  You should look into what is available for you after you decide how you will proceed.  More later. SPY is a ETF, think of it as a share of stock.  You can go to a bank, broker, or what have you and set up an account and buy shares of it.  Then you have x shares of SPY which is the ETF version of SPDR which is an index mutual fund. If the company is matching the first 10% of your income on a 1:1 basis, that would be the best I've heard of in the past two decades, even with the 10 year vesting requirement.  If this is them matching 1 dollar in 10 that you contribute to 401k, it may be the worst I've ever heard of, especially with 10 year vesting.  Typical is 3-5% match, 3-5 year vesting. Bottom line, that match is free money.  And the tax advantage should not be ignored, even if there is no match. Research: I applaud your interest.  The investments you make now will have the greatest impact on your retirement.   Here's a scenario:  If you can figure out how to live on 50% of your take home pay (100k * 0.90 * 0.60 * 0.5 / 12) (salary with first 10% in 401k at roughly 60% after taxes, social security, medicare, etc. halved and divided by 12 for a monthly amount), you'll have 2250 a month to live on.  Since you're 28 and single, it's far easier for you to do than someone who is 50 and married with kids.  That leaves you with 2250 a month to max out 401k and Roth and invest the rest in wealth building.  After four or five years the amount your investments are earning will begin to be noticeable.  After ten years or so, they will eclipse your contributions.  At that point you could theoretically live of the income.  This works with any percentage rate, and the higher your savings rate is, the lower your cost of living amount is, and the faster you'll hit an investment income rate that matches your cost of living amount.  At least that's the early retirement concept.   The key, as far as I can tell, is living frugally, identifying and negating wasteful spending, and getting the savings rate high without forcing yourself into cheap behavior.  Reading financial independence blog posts tells me that once they learn to live frugally, they enjoy it.   It's a lot of work, and planning, but if you want to be financially independent, you are definitely in a good position to consider it. Other notes:" The closest I can think of from the back of my head is http://finviz.com/map.ashx, which display a nice map and allows for different intervals. It has different scopes (S&P500, ETFs, World), but does not allow for specific date ranges, though.