Investing in low cost index fund — does the timing matter?
If you're worried about investing all at once, you can deploy your starting chunk of cash gradually by investing a bit of it each month, quarter, etc. (dollar-cost averaging).  The financial merits and demerits of this have been debated, but it is unlikely to lose you a lot of money, and if it has the psychological benefit of inducing you to invest, it can be worth it even if it results in slightly less-than-optimal gains. More generally, you are right with what you say at the end of your question: in the long run, when you start won't matter, as long as you continue to invest regularly.  The Boglehead-style index-fund-based theory is basically that, yes, you might save money by investing at certain times, but in practice it's almost impossible to know when those times are, so the better choice is to just keep investing no matter what.  If you do this, you will eventually invest at high and low points, so the ups and downs will be moderated. Also, note that from this perspective, your example of investing in 2007 is incorrect.  It's true that a person who put money in 2007, and then sat back and did nothing, would have barely broken even by now.  But a person who started to invest in 2007, and continued to invest throughout the economic downturn, would in fact reap substantial rewards due to continued investing throughout the post-2007 lows.  (Happily, I speak from experience on this point!) Yes timing does matter. Using a simple Rate of Change indicator over the past 100 days and smoothed out with a 50 day Moving Average, I have plotted the S&P 500 since the start of 2007.  The idea is to buy when the ROC indicator crosses above the zero line and sell when the ROC indicator crosses below the zero line. I have compared the results below of timing the markets from the start of 2007 to dollar cost averaging starting from the start of 2007 and investing every 6 months. $80k is invested in both cases.  For the timing the market option $80k was invested at the start of 2007, then the total figure was sold out when a sell signal was given, then the total amount reinvested when a new buy signal was given. For the DCA option $5000 was invested every 6 months starting from the start of 2007 until the last investment at the start of July 2014. The results are below:  Timing the markets results in more than double the returns (not including dividends and brokerage). Edit It has been brought up that I haven't considered tax in my Timing the Market option. So I have updated my timing the market spread-sheet to take into account both long-term and short-term CGT in the USA for someone on the highest tax bracket. The results are below:  The result is still almost a 2x higher returns for the timing the markets option.  Also note that even with the DCA option you will have to sell one day and pay CGT on any profits there. However, the real danger with the DCA option is if you need to sell during a market downturn and not make any profits at all. When you start investing makes a very large difference to the outcome, but that is on the time scale of what generation you were born into, not what week you choose to open your 401(k).  As you note in your last sentence, there is nothing that you can do about this, so there is no point in worrying about it. If you could successfully market time successfully, then that would make a difference even at smaller time scales.  But you probably can't, so there is no point in worrying about that either. As BrenBarn points out, your statement about not regaining their net worth until 2013 applies to someone who invested a lump sum at the 2007 peak, not to someone who invested continuously throughout.   By my calculation, if you started continuously investing in a broad market index at the peak (around Jun 4, 2007), you would have recovered your net worth (relative to investing in a safe instrument that merely kept up with inflation, a hard thing to find these days) around April 12, 2010.  I've done the computation on each business day because that is easier, so it might be slightly worse if do the periodic investment on each payday which is much more realist for a 401(k). (And of course if you need to preserve/recover you net worth in 3 years, you shouldn't be in stocks in the first place) A much less verbose answer is.  Don't worry about buying low.  You have a whole lifetime to dollar cost average your retirement dollars.
"First, two preliminaries, to address good points people made in comments. As AbraCadaver noted, before you move your $30k to something that might lose money, make sure you have enough cash to serve as an emergency fund in case you lose your income. Especially remember that big stock market crashes often go hand-in-hand with widespread layoffs. Also, you mentioned that you're maxed out in a 401k. As JoeTaxpayer hinted, this could very well already be invested in stocks, and, if it isn't, probably a big part of it should be. Regarding your $30k, you don't need to pay anybody. In general, fees and expenses can form a big drag on your investments, and it's good to avoid them as much as possible. In particular, especially with ""only"" $30k, it's unlikely that advisers can save you more than they cost. Also, all financial advisers have a cost: the ""free"" ones usually push you into investing in expensive funds that make them money at your expense. In that regard, keep in mind that, unlike a lawyer or a doctor, a financial adviser is not required by law to give advice that's in your best interest. When investing, there is a pretty short list of important considerations that you should keep in mind: (If anyone has any other points they think are similarly important, feel free to suggest an edit.) Practically speaking, I'd suggest investing in index funds. These are mutual funds that invest very broadly, in a ""passive"" way that doesn't spend a lot of effort (and money) trying to pick individual high-performing stocks or anything like that. Index funds provide a lot of diversification and tend to have low expense ratios. (Other, ""actively managed"" funds tend to be more expensive and often don't outperform index funds anyway.) If you're saving for retirement, there are even target date funds that are themselves composed of a small number of index funds (often domestic and international stocks and bonds), and will increase the proportion invested in bonds (safer) as they get closer to a target retirement date. See, for example the Vanguard Target Retirement 2045 fund. A fund like that one might be all you need if you are saving for retirement. Finally, you can invest online without paying any advisers. Not all companies are created equal, however; do your research. I personally highly recommend Vanguard, since they have a wide variety of no-load index funds and tend to have very low expense ratios. (No-load means you don't have to pay a fee to buy and sell.) Part of why they are inexpensive is that, unlike most financial companies, they are actually a cooperative owned by those who invest in their funds, so they don't need to try and milk a profit out of you. (Don't let that suggest that they're some ""small-potatoes hippie firm"", though: they're actually one of the largest.) I hope I helped. Keep posting if you have more questions!" "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." With a long enough time horizon, no matter when you buy, equities almost always outperform cash and bonds. There's an article here with some info: http://www.fool.co.uk/investing-basics/how-when-and-where-to-invest/ Holding period where shares have beaten cash  There was a similar study done which showed if you picked any day in the last 100 years, no matter if the market was at a high or low, after 1 year your probability of being in profit was only 0.5, but after 10-20 years it was almost certainly 1.0.  Equities compound dividends too, and the best place to invest is in diversified stock indices such as the S&P500, FTSE100, DOW30 or indices/funds which pay dividends. The best way to capture returns is to dollar cost average (e.g. place a lump sum, then add $x every month), to re-invest dividends, and oh, to forget about it in an IRA or SIPP (Self invested pension) or other vehicle which discourages tampering with your investment.  Yes, values rise and fall but we humans are so short sighted, if we had bought the S&P in 2007 and sold in 2009 in fear, we would have missed out on the 25% gain (excluding dividends) from 2007-2014. That's about 3% a year gain even if you bought the 2007 high -beating cash or bonds even after the financial crisis. Now imagine had you dollar cost averaged the entire period from 2007-2014 where your gain would be. Your equity curve would have the same shape as the S&P (with its drastic dip in 2009) but an accelerated growth after. There are studies if you dig that demonstrate the above. From experience I can tell you timing the market is nigh impossible and most fund managers are unable to beat the indices. Far better to DCA and re-invest dividends and not care about market gyrations! .. So I did some queries on Google Scholar, and the term of art academics seem to use is target date fund. I notice divided opinions among academics on the matter. W. Pfau gave a nice set of citations of papers with which he disagrees, so I'll start with them. In 1969, Paul Sameulson published the paper Lifetime Portfolio Selection By Dynamic Stochaistic Programming, which found that there's no mathematical foundation for an age based risk tolerance. There seems to be a fundamental quibble relating to present value of future wages; if they are stable and uncorrelated with the market, one analysis suggests the optimal lifecycle investment should start at roughly 300 percent of your portfolio in stocks (via crazy borrowing). Other people point out that if your wages are correlated with stock returns, allocations to stock as low as 20 percent might be optimal. So theory isn't helping much. Perhaps with the advent of computers we can find some kind of empirical data. Robert Shiller authored a study on lifecycle funds when they were proposed for personal Social Security accounts. Lifecycle strategies fare poorly in his historical simulation: Moreover, with these life cycle portfolios, relatively little is contributed when the allocation to stocks is high, since earnings are relatively low in the younger years. Workers contribute only a little to stocks, and do not enjoy a strong effect of   compounding, since the proceeds of the early investments are taken out of the stock   market as time goes on. Basu and Drew follow up on that assertion with a set of lifecycle strategies and their contrarian counterparts: whereas a the lifecycle plan starts high stock exposure and trails off near retirement, the contrarian ones will invest in bonds and cash early in life and move to stocks after a few years. They show that contrarian strategies have higher average returns, even at the low 25th percentile of returns. It's only at the bottom 5 or 10 percent where this is reversed. One problem with these empirical studies is isolating the effect of the glide path from rebalancing. It could be that a simple fixed allocation works plenty fine, and that selling winners and doubling down on losers is the fundamental driver of returns. Schleef and Eisinger compare lifecycle strategy with a number of fixed asset allocation schemes in Monte Carlo simulations and conclude that a 70% equity, 30% long term corp bonds does as well as all of the lifecycle funds. Finally, the earlier W Pfau paper offers a Monte Carlo simulation similar to Schleef and Eisinger, and runs final portfolio values through a utility function designed to calculate diminishing returns to more money. This seems like a good point, as the risk of your portfolio isn't all or nothing, but your first dollar is more valuable than your millionth. Pfau finds that for some risk-aversion coefficients, lifecycles offer greater utility than portfolios with fixed allocations. And Pfau does note that applying their strategies to the historical record makes a strong recommendation for 100 percent stocks in all but 5 years from 1940-2011. So maybe the best retirement allocation is good old low cost S&P index funds! Remember that unless you participate in the actual fund that these individuals offer to the public, you will not get the same returns they will. If you instead do something like, look at what Warren Buffet's fund bought/sold yesterday (or even 60 minutes ago), and buy/sell it yourself, you will face 2 obstacles to achieving their returns: 1) The timing difference will mean that the value of the stock purchased by Warren Buffet will be different for your purchase and for his purchase. Because these investors often buy large swathes of stock at once, this may create large variances for 2 reasons: (a) simply buying a large volume of a stock will naturally increase the price, as the lowest sell orders are taken up, and fewer willing sellers remain; and (b) many people (including institutional investors) may be watching what someone like Warren Buffet does, and will want to follow suit, chasing the same pricing problem. 2) You cannot buy multiple stocks as efficiently as a fund can. If Warren Buffet's fund holds, say, 50 stocks, and he trades 1 stock per day [I have absolutely no idea about what diversification exists within his fund], his per-share transaction costs will be quite low, due to share volume. Whereas for you to follow him, you would need 50 transactions upfront, + 1 per day. This may appear to be a small cost, but it could be substantial. Imagine if you wanted to invest 50k using this method - that's $1k for each of 50 companies. A $5 transaction fee would equal 1% of the value of each company invested [$5 to buy, and $5 to sell]. How does that 1% compare to the management fee charged by the actual fund available to you? In short, if you feel that a particular investor has a sound strategy, I suggest that you consider investing with them directly, instead of attempting to recreate their portfolio. Some index funds offer lower expense ratios to those who invest large amounts of money. For example, Vanguard offers Admiral Shares of many of its mutual funds (including several index funds) to individuals who invest more than $50K or $100K, and these Shares have lower expense ratios than the Investor shares in the fund. There are Institutional Shares designed for investments by pension plans, 401k plans of large companies etc which have even lower expenses than Admiral Shares. Individuals working for large companies sometimes get access to Institutional Shares through their 401k plans.  Thus, there is something to gained by investing in just one index fund (for a particular index) that offers lower expense ratios for large investments instead of diversifying into several index funds all tracking the same index. Of course, this advantage might be offset by failure to track the index closely, but this tracking should be monitored not on a daily basis but over much longer periods of time to test whether your favorite fund is perennially trailing the index by far more than its competitors with larger expense ratios. Remember that the Net Asset Value (NAV) published by each mutual fund after the markets close already take into account the expense ratio. "When you hear advice to buy index funds, that usually comes with two additional pieces of investment discipline advice that are important: These two elements are important to give you relative predictability in your outcome 20 years from now.  In this old blog post of mine I linked to Warren Buffett talking about this, also  mentioned it in a comment on another answer: http://blog.ometer.com/2008/03/27/index-funds/ It's perfectly plausible to do poorly over 20 years if you buy 100% stocks at once, without dollar-cost averaging or rebalancing. It's very very very plausible to do poorly over 10 years, such as the last 10 in fact. Can you really say you know your financial situation in 20-30 years, and for sure won't need that money? Because predictability is important, I like buying a balanced fund and not ""pure stocks"": http://blog.ometer.com/2010/11/10/take-risks-in-life-for-savings-choose-a-balanced-fund/ (feel a little bad linking to my blog, but retyping all that into this answer seems dumb!) Here's another tip. You can go one step past dollar cost averaging and try value averaging: http://www.amazon.com/Value-Averaging-Strategy-Investment-Classics/dp/0470049774 However, chances are you aren't even going to be good about rebalancing if it's done ""by hand,"" so personally I would not do value averaging unless you can find either a fund or a financial advisor to do it for you automatically. (Finance Buff blog makes a case for a financial advisor, in case you like that more than my balanced fund suggestion: http://thefinancebuff.com/the-average-investor-should-use-an-investment-advisor-how-to-find-one.html) Like rebalancing, value averaging makes you buy more when you're depressed about the market and less when it's exciting. It's hard.  (Dollar cost averaging is easily done by setting up automatic investment, of course, so you don't have to do it manually in the way you would with value averaging.) If you read the usual canonical books on index funds and efficient markets it's easy to remember the takeaway that nobody knows whether the market will go up or down, and yes you won't successfully time the market. But what you can do successfully is use an investment discipline with risk control: assume that the market will fluctuate, that both up and down are likely and possible, and optimize for predictability in light of that. Most importantly, optimize to take your emotions and behavior out of the picture. Some disciplines for example are: there are dozens out there, many of them snake oil, I think these I mentioned are valid. Anyway, you need some form of risk control, and putting all your money in stocks at once doesn't give you a lot of risk control. There's no real need to get creative. A balanced fund that uses index funds for equity and bond portions is a great choice." I don't think it has to be either-or. You can profitably invest inside the SIMPLE. (Though I wouldn't put in any more than the 1% it takes to get the match.) Let's look at some scenarios. These assume salary of $50k/year so the numbers are easy. You can fill in your own numbers to see the outcome, but the percentages will be the same. Let it sit in cash in the SIMPLE. You put in 1%, your employer matches with 1%. Your account balance is $1,000 (at the end of the year), plus a small amount of interest. Cost to you is $500 from your gross pay. 100% return on your contributions, yay! Likely 0-1% real returns going forward; you'll be lucky to keep up with inflation over the long term. Short term not so bad. Buy shares of index ETFs in the SIMPLE; let's assume the fee works out to 10%. You put in 1%, employer matches 1%. Your contributions are $500, fees are $100, your balance is $900 in ETFs. 80% instant return, and possible 6-7% real long term returns going forward. Buy funds in the SIMPLE; assume the load is 5%, management fee is 1% and you can find something that behaves like an index fund (so it is theoretically comparable to above). 1% from you, 1% from employer. Your contributions are $500, load fees are $50, your balance is $950. 90% instant return, and possible 5-6% real long term returns going forward (assuming the 6-7% real returns of equities are reduced by the 1% management fee). (You didn't list out the fees, and they're probably different for the different fund choices, so fill in your own details and do the math.) Invest outside the SIMPLE in the same ETFs or equivalent no load index funds; let's assume you can do this with no fees. You put in the same 1% of your gross (ignoring any difference that might come from paying FICA) into a self directed traditional IRA. At the end of the year the balance is $500. So deciding whether or not to take the match is a no brainer: take it. Deciding whether you should hold cash, ETFs, or (one of two types of) funds in your SIMPLE is a little trickier.