How do I invest in the S&P 500?
The S&P 500 is a stock market index, which is a list of 500 stocks from the largest companies in America. You could open a brokerage account with a broker and buy shares in each of these companies, but the easiest, least expensive way to invest in all these stocks is to invest in an S&P 500 index mutual fund. Inside an index mutual fund, your money will be pooled together with everyone else in the fund to purchase all the stocks in the index.  These types of funds are very low expense compared to managed mutual funds.  Most mutual fund companies have an S&P 500 index fund; two examples are Vanguard and Fidelity.  The minimum investment in most of these mutual funds is low enough that you will be able to open an account with your $4000. Something you need to keep in mind, however: investing in any stock mutual fund is not non-risk.  It's not even low-risk, really.  It is very possible to lose money by investing in the stock market.  An S&P 500 index fund is diversified in the sense that you have money in lots of different stocks, but it is also not diversified, in a sense, because it is all in large cap American stocks.  Before investing in the stock market, you should have a goal for the money you are investing.  If you are investing for something several years away, an index fund can be a good place to invest, but if you will need this money within the next few years, the stock market might be too risky for you. "Buy the ETF with ticker ""SPY"".  This will give you exposure to exactly the S&P 500 stocks,  This is similar to the mutual fund suggestion by Ben Miller, except that the ETF has several advantages over mutual funds, especially as regards taxes.  You can find information on the difference between ETF and mutual fund in other questions on this site or by searching the web."
From Wikipedia -  To calculate the value of the S&P 500 Index, the sum of the adjusted   market capitalization of all 500 stocks is divided by a factor,   usually referred to as the Divisor. For example, if the total adjusted   market cap of the 500 component stocks is US$13 trillion and the   Divisor is set at 8.933 billion, then the S&P 500 Index value would be   1,455.28. From a strictly mathematical perspective, the divisor is not canceling out the units, and the S&P index is dollar denominated even though it's never quoted that way. A case in point is that the S&P is often said to have a P/E, and especially an E, the earnings attributed to one 'unit' of S&P. And if you buy a mutual fund sporting a low expense ratio, you can invest exactly that much money (the current S&P index value) and see the dividends accrue to your account, less the fee. Exchange-traded funds are bought and sold like stocks so you'd be able to place stop orders on them just like you could for individual stocks. For example, SPY would be the ticker for an S & P 500 ETF known as a SPDR. Open-end mutual funds don't have stop orders because of how the buying and selling is done which is on unknown prices and often in fractional shares. For example, the Vanguard 500 Index Investor shares(VFINX) would be an example of an S & P 500 tracker here. "There is no simple answer to that, because no one knows exactly what the probability distribution of S&P 500 returns is. Here is a sketch of one possible way to proceed. Don't forget step 4!  The problem is that the stock market is full of surprises, so this kind of ""backtesting"" can only reliably tell you about what already happened, not what will happen in the future.  People argue about how much you can learn from this kind of analysis.  However, it is at the least a clearly defined and objective process.  I wouldn't advise investing your whole nest egg in anything based just on this, but I do think that it is relevant information." The point of buying an index fund is that you don't have to pick winners. As long as the winners are included in the index fund (which can include far more than 500 stocks), you benefit on average because of overall upward historical market performance. Picking only the top 50 capitalized stocks in the S&P 500 does not guarantee you will successfully track the S&P 500 index because the stocks in the tail can account for an outsized amount of overall growth; the top 50 stocks by market capitalization change over time, and these stocks are not necessarily the stocks that perform better.  As direct example, the 10 year average annual return for the S&P top 50 is 4.52%, while the 10 year average annual return for the S&P 500 is 5.10%. Issues of trading and balancing to maintain these aside, these indices are not the same. "NYT republished a nifty infographic that shows how the S&P 500 performs over various time horizons. If you study it for a bit, you'll see that 10 percent is not likely over time that you'll earn 10 percent annually after inflation. Most people quoting the higher number are working with numbers before inflation.  The above linked chart is misleading in the following sense: it groups into five categories, who's boundaries are demarcated by percentages of interest. But we'd rather see them clustered by those percentages. For example, 6.9 percent falls into the neutral category (better than investing in fixed interest securities, but still below market average), but 7.1 falls into the ""above average"" category. The effect is that we will treat the neutral color that dominates the long term trend as being somewhere in the middle of 3-7, when I suspect that's not the case. Some day I'll probably make my own version and see how that plays out.  So that all said, if you look at the 30 year diagonal, you can see there's still quite a bit of variation in returns. Unfortunately I can't turn this into a single number for you, but grab a spreadsheet and some market data if you want one." I would be very cautious about investing any more funds into the S&P500 at this stage. You are quite correct in your observation with the charts regarding the 2001 and 2008 crashes, and below is the chart of the S&P500 over the last 20 years with some indicators on it.  The green line on the price chart is the 100 week Moving Average (MA) and the pink line below the price chart is the Moving Average of the Rate of Change (ROC) Indicator. In general the market is moving up if price is above the 100 week MA and the ROC is above 0%, and vise-versa the market is moving down if price is below the 100 week MA and the ROK is below 0%. Both times in 2001 and in 2008 when prices broke below the 100 week MA and then the ROC crossed below the zero line, well we all know what happened next. In 2001 prices kept falling and the ROC didn't cross back above zero for about 2.5 years, in 2008 much the same happened and the ROC didn't cross back above zero for over 20 months. Now as we are reaching the end of 2015 prices have once again broken below the 100 week MA and the ROC is just above the zero line quickly heading down towards it. If you have a 5 to 8 year time frame, and prices do continue to fall much further after the ROC crosses below the zero line, your current funds and any new funds you invest in this ETF will potentially see heavy losses for the next one to two years and then take another year to two years or more to recover to current levels. This means that your funds will potentially have no gains at all in 5 or 6 years time. A better option is to get out of the market once the ROC crosses below zero and then look to get back in once the recovery has started, when the ROC crosses back above the Zero line. You might be out of the market for a year or two, but once you get back in you can expect robust gains over the next 3 to 5 years. If you do get out and things reverse quite quickly you can easily just get back in. In mid-2010 and mid-2011 the price broke below the 100 week MA but the ROC remained above Zero and prices continued moving up after short corrections. In mid-2012 the ROC got very close to the Zero line but did not cross below it, and again prices continued to go up after a small correction. You should plan for the worst and be ready if it occurs. If you don't plan you're just hoping and hoping is what will keep you awake at night whist things are going against you. The best way I know of is to join an investment club.  They club will act like a mutual fund, investing in stocks researched and selected by the group.  Taking part in research and presenting results to the group for peer review is an excellent way to learn.  You'll learn what is a good reason to invest and what isn't. You'll probably pick both winners and losers. The goal of participation is education.  Some people learn how to invest and continue happily doing so. Others learn how to invest in single stocks and learn it is not for them. Today SPY (The S&P ETF) trades at $128. The option to buy at $140 (this is a Jan '13 call) trades for $5.  I buy the call, for $500 as they trade in 100 lots.  The S&P skyrockets to 1500 and SPY to $150. The call trades for $11, as it still has a month or two before expiring, so I sell it, and get $1100. The S&P rose 17%, but I doubled my money. If it 'only' rose 9%, to less than $140, I'd lose my investment. No, I don't need to buy the SPY I can sell the call any time before expiration. In fact, most options are not exercised, they are sold between purchase and expiration date.