How should I be investing in bonds as part of a diversified portfolio?
For most people, you don't want individual bonds. Unless you are investing very significant amounts of money, you are best off with bond funds (or ETFs). Here in Canada, I chose TDB909, a mutual fund which seeks to roughly track the DEX Universe Bond index. See the Canadian Couch Potato's recommended funds. Now, you live in the U.S. so would most likely want to look at a similar bond fund tracking U.S. bonds. You won't care much about Canadian bonds. In fact, you probably don't want to consider foreign bonds at all, due to currency risk. Most recommendations say you want to stick to your home country for your bond investments. Some people suggest investing in junk bonds, as these are likely to pay a higher rate of return, though with an increased risk of default. You could also do fancy stuff with bond maturities, too. But in general, if you are just looking at an 80/20 split, if you are just looking for fairly simple investments, you really shouldn't. Go for a bond fund that just mirrors a big, low-risk bond index in your home country. I mean, that's the implication when someone recommends a 60/40 split or an 80/20 split. Should you go with a bond mutual fund or with a bond ETF? That's a separate question, and the answer will likely be the same as for stock mutual funds vs stock ETFs, so I'll mostly ignore the question and just say stick with mutual funds unless you are investing at least $50,000 in bonds. Buy a fund of bonds, there are plenty and are registered on your stockbroker account as 'funds' rather than shares. Otherwise, to the individual investor, they can be considered as the same thing. Funds (of bonds, rather than funds that contain property or shares or other investments) are often high yield, low volatility. You buy the fund, and let the manager work it for you. He buys bonds in accordance to the specification of the fund (ie some funds will say 'European only', or 'global high yield' etc) and he will buy and sell the bonds regularly. You never hold to maturity as this is handled for you - in many cases, the manager will be buying and selling bonds all the time in order to give you a stable fund that returns you a dividend. Private investors can buy bonds directly, but its not common.  Should you do it? Up to you. Bonds return, the company issuing a corporate bond will do so at a fixed price with a fixed yield. At the end of the term, they return the principal. So a 20-year bond with a 5% yield will return someone who invests £10k, £500 a year and at the end of the 20 years will return the £10k. The corporate doesn't care who holds the bond, so you can happily sell it to someone else, probably for £10km give or take. People say to invest in bonds because they do not move much in value. In financially difficult times, this means bonds are more attractive to investors as they are a safe place to hold money while stocks drop, but in good times the opposite applies, no-one wants a fund returning 5% when they think they can get 20% growth from a stock.
Fire your fund manager. There are several passive funds that seek to duplicate the S&P 500 Index returns. They have lower management fees, which will make returns lower than S&P, and they have less risk by following a broadly diversified strategy (versus midcap growing stocks). There's also ETFs, but evidence is growing that they're not as safe as hoped. But here's the deal: the S&P has been on a tear lately. It could be overvalued and what looks like a good investment could start falling again. A possible alternative would be one of the Lifetime funds that seek to perform portfolio adjustment with a retirement decade target; they're fairly new which mostly means nobody knows how they screw you over yet. In theory, this decade structure means the brokerage can execute trading cash for stocks, stocks for bonds, and bonds for cash in house. "Typically you diversify a portfolio to reduce risk. The S&P 500 is a collection of large-cap stocks; a diversified portfolio today probably contains a mix of large cap, small cap, bonds,  international equity and cash. Right now, if you have a bond component, that part of your portfolio isn't performing as well. The idea of diversification is that you ""smooth out"" the ups and downs of the market and come out ahead in most situations. If you don't have a bond or cash component in your portfolio, you may have picked (or had someone pick for you) lousy funds.  Without more detail, that's about all that can be said. EDIT: You provided more detail, so I want to add a little to my answer. Basically, you're in a fund that has high fees (1.58% annually) and performance that trails the mid-cap index. The S&P 500 is a large-cap index (large cap == large company), so a direct comparison is not necessarily meaningful. Since you seem to be new at this, I'd recommend starting out with the Vanguard Total Stock Market Index Fund (VTSMX) or ETF (VTI). This is a nice option because it represents the entire stock market and is cheap... it's a good way to get started without knowing alot. If your broker charges a transaction fee to purchase Vanguard funds and you don't want to change brokers or pay ETF commissions, look for or ask about transaction-fee free ""broad market"" indexes. The expense ratio should be below 0.50% per year and optimally under 0.20%. If you're not having luck finding investment options, swtich to a discount broker like TD Ameritrade, Schwab, ScottTrade or Fidelity (in no particular order)" You're missing the concept of systemic risk, which is the risk of the entire market or an entire asset class. Diversification is about achieving a balance between risk and return that's appropriate for you. Your investment in Vanguard's fund, although diversified between many public companies, is still restricted to one asset class in one country. Yes, you lower your risk by investing in all of these companies, but you don't erase it entirely.  Clearly, there is still risk, despite your diversification. You may decide that you want other investments or a different asset allocation that reduce the overall risk of your portfolio. Over the long run, you may earn a high level of return, but never forget that there is still risk involved. bonds seem pretty worthless, at least until I retire According to your profile, you're about my age. Our cohort will probably begin retiring sometime around 2050 or later, and no one knows what the bond market will look like over the next 40 years. We may have forecasts for the next few years, but not for almost four decades. Writing off an entire asset class for almost four decades doesn't seem like a good idea. Also, bonds are like equity, and all other asset classes, in that there are different levels of risk within the asset class too. When calculating the overall risk/return profile of my portfolio, I certainly don't consider Treasuries as the same risk level as corporate bonds or high-yield (or junk) bonds from abroad.  Depending on your risk preferences, you may find that an asset allocation that includes US and/or international bonds/fixed-income, international equities, real-estate, and cash (to make rebalancing your asset allocation easier) reduces your risk to levels you're willing to tolerate, while still allowing you to achieve returns during periods where one asset class, e.g. equities, is losing value or performing below your expectations. "Diversification is the only real free lunch in finance (reduction in risk without any reduction in expected returns), so clearly every good answer to your question will be ""yes.""  Diversification is good.""  Let's talk about many details your question solicits. Many funds are already pretty diversified.  If you buy a mutual fund, you are generally already getting a large portion of the gains from diversification.  There is a very large difference between the unnecessary risk in your portfolio if you only hold a couple of stocks and if you hold a mutual fund.  Should you be diversified across mutual funds as well?  It depends on what your funds are.  Many funds, such as target-date funds, are intended to be your sole investment.  If you have funds covering every major asset class, then there may not be any additional benefit to buying other funds. You probably could not have picked your ""favorite fund"" early on.  As humans, we have cognitive biases that make us think we knew things early on that we did not.  I'm sure at some point at the very beginning you had a positive feeling toward that fund.  Today you regret not acting on it and putting all your money there.  But the number of such feelings is very large and if you acted on all those, you would do a lot of crazy and harmful things.  You didn't know early on which fund would do well.  You could just as well have had a good feeling about a fund that subsequently did much worse than your diversified portfolio did. The advice you have had about your portfolio probably isn't based on sound finance theory.  You say you have always kept your investments in line with your age.  This implies that you believe the guidelines given you by your broker or financial advisor are based in finance theory.  Generally speaking, they are not.  They are rules of thumb that seemed good to someone but are not rigorously proven either in theory or empirics.  For example the notion that you should slowly shift your investments from speculative to conservative as you age is not based on sound finance theory.  It just seems good to the people who give advice on such things.  Nothing particularly wrong with it, I guess, but it's not remotely on par with the general concept of being well-diversified.  The latter is extremely well established and verified, both in theory and in practice.  Don't confuse the concept of diversification with the specific advice you have received from your advisor. A fund averaging very good returns is not an anomaly--at least going forward it will not be.  There are many thousand funds and a large distribution in their historical performance.  Just by random chance, some funds will have a truly outstanding track record.  Perhaps the manager really was skilled.  However, very careful empirical testing has shown the following: (1) You, me, and people whose profession it is to select outperforming mutual funds are unable to reliably detect which ones will outperform, except in hindsight  (2) A fund that has outperformed, even over a long horizon, is not more likely to outperform in the future. No one is stopping you from putting all your money in that fund. Depending on its investment objective, you may even have decent diversification if you do so.  However, please be aware that if you move your money based on historical outperformance, you will be acting on the same cognitive bias that makes gamblers believe they are on a ""hot streak"" and ""can't lose.""  They can, and so can you. ======== Edit to answer a more specific line of questions =========== One of your questions is whether it makes sense to buy a number of mutual funds as part of your diversification strategy.  This is a slightly more subtle question and I will indicate where there is uncertainty in my answer.   Diversifying across asset classes.  Most of the gains from diversification are available in a single fund.  There is a lot of idiosyncratic risk in one or two stocks and much less in a collection of hundreds of stocks, which is what any mutual fund will hold.  Still,you will probably want at least a couple of funds in your portfolio.  I will list them from most important to least and I will assume the bulk of your portfolio is in a total US equity fund (or S&P500-style fund) so that you are almost completely diversified already. Risky Bonds.  These are corporate, municipal, sovereign debt, and long-term treasury debt funds. There is almost certainly a good deal to be gained by having a portion of your portfolio in bonds, and normally a total market fund will not include bond exposure.  Bonds fund returns are closely related to interest rate and inflation changes.  They are also exposed to some market risk but it's more efficient to get that from equity.  The bond market is very large, so if you did market weights you would have more in bonds than in equity.  Normally people do not do this, though.  Instead you can get the exposure to interest rates by holding a lesser amount in longer-term bonds, rather than more in shorter-term bonds.  I don't believe in shifting your weights toward nor away from this type of bond (as opposed to equity) as you age so if you are getting that advice, know that it is not well-founded in theory.  Whatever your relative weight in risky bonds when you are young is should also be your weight when you are older. International. There are probably some gains from having some exposure to international markets, although these have decreased over time as economies have become more integrated.  If we followed market weights, you would actually put half your equity weight in an international fund.  Because international funds are taxed differently (gains are always taxed at the short-term capital gains rate) and because they have higher management fees, most people make only a small investment to international funds, if any at all. Emerging markets  International funds often ignore emerging markets in order to maintain liquidity and low fees.  You can get some exposure to these markets through emerging markets funds.  However, the value of public equity in emerging markets is small when compared with that of developed markets, so according to finance theory, your investment in them should be small as well.  That's a theoretical, not an empirical result. Emerging market funds charge high fees as well, so this one is kind of up to your taste.  I can't say whether it will work out in the future. Real estate.  You may want to get exposure to real estate by buying a real-estate fund (REIT).  Though, if you own a house you are already exposed to the real estate market, perhaps more than you want to be.  REITs often invest in commercial real estate, which is a little different from the residential market. Small Cap.  Although total market funds invest in all capitalization levels, the market is so skewed toward large firms that many total market funds don't have any significant small cap exposure.  It's common for individuals to hold a small cap fund to compensate for this, but it's not actually required by investment theory.  In principle, the most diversified portfolio should be market-cap weighted, so small cap should have negligible weight in your portfolio.  Many people hold small cap because historically it has outperformed large cap firms of equal risk, but this trend is uncertain.  Many researchers feel that the small cap ""premium"" may have been a short-term artifact in the data.  Given these facts and the fact that small-cap funds charge higher fees, it may make sense to pass on this asset class.  Depends on your opinion and beliefs. Value (or Growth) Funds.  Half the market can be classed as ""value"", while the other half is ""growth.""  Your total market fund should have equal representation in both so there is no diversification reason to buy a special value or growth fund.  Historically, value funds have outperformed over long horizons and many researchers think this will continue, but it's not exactly mandated by the theory.  If you choose to skew your portfolio by buying one of these, it should be a value fund. Sector funds.  There is, in general, no diversification reason to buy funds that invest in a particular sector.  If you are trying to hedge your income (like trying to avoid investing in the tech sector because you work in that sector) or your costs (buying energy because you buy use a disproportionate amount of energy) I could imagine you buying one of these funds. Risk-free bonds.  Funds specializing in short-term treasuries or short-term high-quality bonds of other types are basically a substitute for a savings account, CD, money market fund, or other cash equivalent.  Use as appropriate but there is little diversification here per se. In short, there is some value in diversifying across asset classes, and it is open to opinion how much you should do.  Less well-justified is diversifying across managers within the same asset class.  There's very little if any advantage to doing that." If I invest X each month, where does X go - an existing (low yield)   bond, or a new bond (at the current interest rate)? This has to be viewed in a larger context.  If the fund has outflows greater than or equal to inflows then chances are there isn't any buying being done with your money as that cash is going to those selling their shares in the fund.  If though inflows are greater than outflows, there may be some new purchases or not.  Don't forget that the new purchase could be an existing bond as the fund has to maintain the duration of being a short-term, intermediate-term or long-term bond fund though there are some exceptions like convertibles or high yield where duration isn't likely a factor. Does that just depend on what the fund manager is doing at the time   (buying/selling)? No, it depends on the shares being created or redeemed as well as the manager's discretion. If I put Y into a fund, and leave it there for 50 years, where does Y   go when all of the bonds at the time I made the purchase mature?  You're missing that the fund may buy and sell bonds at various times as for example a long-term bond fund may not have issues nearing maturity because of what part of the yield curve it is to mimic. Does Y just get reinvested in new bonds at the interest rate at that time? Y gets mixed with the other money in the fund that may increase or decrease in value over time.  This is part of the risk in a bond fund where NAV can fluctuate versus a money market mutual fund where the NAV is somewhat fixed at $1/share. I'm assuming you are buying bond mutual funds or bond etfs here, not the actual bonds directly. There are a significant variety of different types of bond funds, reflecting the sort of bonds they invest in. For example, you can invest in risky, non-commercial grade bonds, also known as junk bonds. Or you can invest in short-term bonds, which are much safer but return much less. There's no such thing as the 'average bond'. So, let's go for somewhere in the middle. Let's go for 3% return, after fees. Now, it's fairly simple math. You want $3,000 a month, or $36,000 a year. To generate that sort of return, you'd need to invest $1,200,000. If we are more optimistic, we could go for a 4% return, after fees. That reduces your investment to $900,000. Note that it would almost certainly not make sense to invest all that money in bonds. Instead, you'd want to invest in a mix of stocks and bonds. This could likely reduce your risk while increasing your expected return. If liquidity and cost are your primary objectives, Vanguard is indeed a good bet.  They are the walmart of finance and the absolute best at minimizing fees and other expenses. Your main portfolio holding should be VTI, the total stock market fund.  Highly liquid and has the lowest fees out there at 0.05%.  You can augment this with a world-minus-US fund if you want.  No need to buy sector or specific geography funds when you can get the whole market for less. Add some bond funds and alternative investments (but not too much) if you want to be fully diversified. Short-term to intermediate-term corporate bond funds are available. The bond fund vehicle helps manage the credit risk, while the short terms help manage inflation and interest rate risk. Corporate bond funds will have fewer Treasuries bonds than a general-purpose short-term bond fund: it sounds like you're interested in things further out along the risk curve than a 0.48% return on a 5-year bond, and thus don't care for the Treasuries. Corporate bonds are generally safer than stocks because, in bankruptcy, all your bondholders have to be paid in full before any equity-holders get a penny. Stocks are much more volatile, since they're essentially worth the value of their profits after paying all their debt, taxes, and other expenses.  As far as stocks are concerned, they're not very good for the short term at all. One of the stabler stock funds would be something like the Vanguard Equity Income Fund, and it cautions: This fund is designed to provide investors with an above-average level   of current income while offering exposure to the stock market. Since   the fund typically invests in companies that are dedicated to   consistently paying dividends, it may have a higher yield than other   Vanguard stock mutual funds. The fund’s emphasis on slower-growing,   higher-yielding companies can also mean that its total return may not   be as strong in a significant bull market. This income-focused fund   may be appropriate for investors who have a long-term investment goal   and a tolerance for stock market volatility. Even the large-cap stable companies can have their value fall dramatically in the short term. Look at its price chart; 2008 was brutal. Avoid stocks if you need to spend your money within a couple of years. Whatever you choose, read the prospectus to understand the risks.