Bogleheads® investment philosophy

The Bogleheads follow a small number of simple investment principles that have been shown over time to produce risk-adjusted returns far greater than those achieved by the average investor. Many of these ideas are distilled from Nobel prize-winning financial economics research on topics like Modern Portfolio Theory and the Capital Asset Pricing Model. But they are really very easy to understand and to implement, and they work. In fact, the basis of all of these principles is the idea that successful investing is not a complicated process, and can be accomplished by anyone with a small amount of effort.

These ideas come from the investing philosophy of Vanguard-founder Jack Bogle. They have been further distilled and explained in thousands of posts on the Bogleheads forums, particularly by original contributors Taylor Larimore and Mel Lindauer. More advanced concepts were first widely introduced to the Bogleheads community by investing author Larry Swedroe, a tradition that has been carried on by Rick Ferri among many others.

This wiki provides many details about how to apply these principles, given constraints, such as the specific tax-advantaged accounts an investor has available. But as you make specific decisions about what to buy and where to hold it, it helps to keep the big picture in mind. The Bogleheads principles are:

Live below your means
Perhaps the most important idea is that you need to save a significant portion of your income every month, in order to have the money you will need in the future to comfortably retire. There is simply no substitute for spending less than you earn. You also need to avoid debt like credit cards and home equity loans (or pay them off if you have them) and consistently set aside a portion of your earnings for decades. If you don't save enough, no amount of financial trickery will provide the returns you need for a comfortable retirement.

How much is enough? Twenty percent of your income is a good baseline number. If you would like to retire before age 65, or you hope to leave significant assets to charity or your children, you probably want to save even more.

By far the best way to save money is to arrange to have it automatically deducted from your paycheck. For people with 401(k) plans, this happens automatically. For investing in an IRA and/or a taxable account, you should set it up with your fund company to have the money automatically deducted from your bank account the day after pay day. This concept, described as "paying yourself first", goes a long way towards encouraging reasonable spending habits. When you never see the money in your bank account, you are less likely to spend it.

There are specific guidelines as to which accounts you should fund in what order. But first you need to save the money.

Asset allocation (holding bonds) is essential
Owning stocks is necessary to get the return needed for a comfortable retirement. Stocks provide us with a share of the profits generated by the economy. But in exchange for that high return, stocks are extremely volatile. Many investors learned how risky stocks can be in 2008, when they fell 50% off of their previous high. Over time, stocks follow the trend of the economy, which is to grow. But they can have decade-long periods where they do not grow at all. So having the correct allocation to bonds, which can provide ballast for one's portfolio, is also a necessary element of asset allocation. Bonds are a promise to pay back your loan of money on a pre-set schedule. Bonds do not produce the same high returns that stocks do, but they are much less volatile. The way to get reasonable growth without stomach-churning drops is to hold a mix of stocks and bonds.

How much bonds? That's the basic question of allocation. The decision needs to balance your ability and your need to take risk. The more risk you can handle, the less bonds you need. But if you don't have need for a high return (perhaps you've already saved enough to retire), you should hold more in bonds. This lets you reduce the volatility of the stocks in your portfolio.

A good guideline is to hold your age in bonds. When you are younger, you have your prime earning years ahead of you, and you have decades before you need to access the money. So, a big drop in stock prices will not hurt you, as long as it doesn't cause you to flee the market. As you age, you can afford to take less and less risk. Many people thought they could deal with large amounts of risk, but found after the crash of 2008 that they psychologically could not. Those people should have been holding more bonds. You need to think very carefully if choosing an asset allocation riskier than your age in bonds.

Many Bogleheads like to own bond funds instead of individual bonds for the convenience and to diversify the risk of any one bond defaulting. We tend to stick to bond funds with short and intermediate-term duration and high credit ratings. We use our bond holdings for safety, and take our risk in equities. Typical Bogleheads bond allocations are between 50% to 100% nominal bonds (such as Vanguard Total Bond Market) and 0-50% inflation-protected securities (such as Vanguard Inflation Protected Securities), with the median being 20% in a recent poll. The nominal bonds provide protection against a deflationary environment, and the inflation-protected bonds offer protection against the ravages of unexpected inflation. Together, they provide the safety or "ballast" that keeps your portfolio steady.

Buy low cost funds that are widely diversified
Rather than trying to pick the specific stocks or sectors of the market that will outperform in the future, Bogleheads buy funds that are widely diversified, or even approximate the whole market. This guarantees that we will receive the average return of all equity investors. Being average sounds bad, but is actually a great thing. That's because the vast majority of investors perform worse than average, after you take into account the high fees they pay for actively managed funds. If there were no fees, then every year, half of all actively managed funds would outperform the index (because the index is the average). It might seem like you would just want to invest in those outperforming funds. But there is no persistence to the results. Funds that outperform one year tend to underperform in the next. And in the real world, you have to pay high fees on managed funds, which means that more than half of those actively managed funds actually underperform index funds every year.

The best and lowest cost way to buy the whole stock market is with index funds (either through traditional mutual funds or ETFs). The first such retail fund was pioneered by Jack Bogle in 1976, and was called "Bogle's folly" by some members of the financial industry. Today, Vanguard Total Stock Market is the largest mutual fund in the world, and also one of the best values, charging fees about one tenth the industry average. By purchasing that one fund, you own a piece of essentially every public company in the US. This diversification lowers your risk, because the failure of any one company does not have a big effect. You are still exposed to the high volatility of the overall stock market, but in exchange you get to participate in the high returns over time.

The difference between an expense ratio of 0.15% and 1.5% might not seem like much, but the effect of the compounding over your investing lifetime is enormous. A fund with a 1.5% expense ratio will provide you with several hundred thousand dollars less for your retirement after 30 years than a 0.15% index fund with the same growth. And remember that most managed funds actually underperform index funds. Costs matter, and investors need their their returns compounding for their own benefit, not being skimmed off in unnecessary fees by your fund company.

Bogleheads also like to use low cost index funds to hold international stocks, so that we can take advantage of economic growth in other countries. Vanguard Total International Stock Market is one such fund that owns a portion of most international public companies in both the developed and developing worlds. International equity may have higher growth over time, but it is even more volatile than domestic stocks. We generally try to hold 20 to 40% of our equity in international.

Unfortunately, some 401(k) plans do not offer any index funds at all. In that case, Bogleheads will generally invest in some of the largest, most diversified funds with the lowest fees. These are sometimes called "closet index funds", because they tend to perform relatively similarly to index funds (although with higher fees). If you need to find the "least-bad" funds available in your 401(k), one of the best ways to start is to look for the funds with the lowest expense ratios.

Tax efficiency matters
Perhaps the reason that Bogleheads focus so carefully on tax efficiency is that we realize that we have no control over what the equity markets might do in a given year. Rather than obsessing over the unknowable, we like to focus on areas where our decisions can save us significant money, by preserving money for our retirement that would otherwise be paid to Uncle Sam. The most important rule for tax efficiency is to take full advantage of tax-advantaged accounts such as 401(k)s and  IRAs. These allow your money to grow, using the magic of compound interest, without a portion being removed every year to pay taxes. Many investors have large enough tax-advantaged accounts to hold all of their retirement savings, and so never need to worry about tax efficient placement.

But for those of us who also have taxable accounts, Bogleheads look carefully at the tax efficiency of each of our holdings. We recognize that some kinds of funds, particularly total market equity index funds, are extremely tax-efficient, because they produce very low dividends and capital gains. By contrast, bond funds are extremely tax-inefficient, because the interest they produce every year is taxed at your full marginal tax rate. So, Bogleheads put our tax-inefficient funds (particularly bonds) into our tax-advantaged accounts. Other tax-inefficient funds that should always go in tax-advantaged accounts are REITs, small value funds, and actively managed funds that frequently churn their holdings. If there's not enough room for your bonds in your tax-advantaged accounts and you are in a higher tax-bracket, you should hold tax-exempt municipal bond funds in your taxable account.

Bogleheads who hold taxable accounts also often make use of Tax Loss Harvesting, which is a technique to turn market downturns into immediate tax savings. The key thing to remember about tax efficiency is that tax-efficient asset placement matters. The same funds can produce hundreds of thousands of dollars more for your retirement if they are placed in a tax efficient manner.

Stay the course
This is perhaps the most challenging part of Bogleheads investing, but is absolutely essential to its success. Bogleheads adopt a reasonable investment plan and then we stay the course. When index funds were dramatically outperforming all the alternatives in the 1990's, this advice was easy to follow. But with the crash of 2008, many investors panicked, or at least wavered in their commitment to buy and hold investing. Bogleheads realize that in exchange for the high returns that stocks produce over time, the equity markets are enormously volatile. After big drops, it can be very difficult to continue to follow one's pre-set plan. Even during more normal markets, there are always distractions, such as attractive new asset classes that have recently outperformed, or fancy alternative investment vehicles such as hedge funds.

Bogleheads do our best not to be distracted, and not to waiver. We create an asset allocation with a large ownership of bonds in order to reduce the volatility of our portfolios and help us stay the course. Once you set up a Bogleheads portfolio, the only real course correction needed is to rebalance once per year (on your birthday, if you want), to bring your stock/bond allocations back to your pre-set levels. (You generally want to increase your bond holdings slightly every year, such as by setting your percentage of bonds to your age.) Although making only that one change every year takes discipline, it is also an enormous relief to be able to tune out the endless chatter of when and what to buy and sell.

There is a large amount of research showing that typical mutual fund investors actually perform far worse than the mutual funds they invest in, because of their tendency to buy after a fund has done well and sell when it is doing poorly. This behavior of buy high, sell low is guaranteed to produce poor results. Instead, Bogleheads put together a good plan and then stick with it, which consistently produces good outcomes.

Variations on Bogleheads investing
Bogleheads follow a set of principles that maximize our chances of a good retirement. But there are many different plans which are compatible with these underlying principles. And some people diverge somewhat on some of the principles, which is OK, in moderation. For example, some of us find financial markets fascinating, and like trying to pick individual stocks. If that sounds like you, we recommend that you set aside 5% of your retirement portfolio as "play money", which you can invest as you see fit. Some people like to follow a "tactical asset allocation" strategy with their 5% play money by moving that portion of their money in and out of stocks based on what they predict the market will do next. Or you could invest in a fund that you will believe will outperform. Just note that even if you have a couple of years of market-beating performance, very few investors are able to beat the risk-adjusted returns of diversified equity index funds over time. So please don't become overconfident.

Other Bogleheads like to invest a portion of their assets in a few carefully-selected actively-managed mutual funds. That's fine, but total market index funds should still make up the bulk of your equity holdings. REITs (such as Vanguard REIT Fund) are also a common addition to some Bogleheads portfolios, since they have sometimes provided additional diversification from equities and bonds. Most managed funds and all REITs are tax-inefficient, and so need to be held in tax-advantaged accounts.

Many Bogleheads, following the research of  Fama and  French, like to slice and dice their equity holdings among multiple asset classes with the goal of overweighting their  small and value holdings relative to the total market. There is a great deal of historical evidence that such a portfolio will produce higher volatility-adjusted returns over time, but only for those investors who can not only manage a more complex allocation plan, but can stick with it through inevitable periods of underperformance. Most, if not all, of the expected benefits of slicing and dicing can be achieved very simply by "tilting" a total market portfolio with the addition of a small value fund (like Vanguard Small Cap Value). But again, such a portfolio has often underperformed a total market portfolio for a decade or more. If you would be discouraged by such underperformance, you should just stick with total market investing.

Conclusion
In summary, a Bogleheads investor tends to save a lot, selects an asset allocation containing both stock and bond asset classes, buys low cost, widely diversified funds, allocates funds tax efficiently, and stays the course. One of the wonderful things about Bogleheads investing is that it generally only requires a part of a day to set up, and then about an hour a year of effort to rebalance. Beyond that, there is no need to watch the markets or follow financial news. Even better, it works. Although Bogleheads investing may seem strangely simple, it is based on decades of comprehensive research showing that buying and holding the whole market consistently outperforms the alternatives.

In addition to learning the details of Bogleheads investing from this wiki, we urge you to visit the Bogleheads forum. You may or may not enjoy some of the endless debates about vagaries such as dollar cost averaging or  non-deductible IRAs. But nearly everyone appreciates the shared commitment to implementing financial plans that enable us to accomplish our life goals. The Bogleheads community is a wonderful place, and you are very welcome there.