How to rebalance a portfolio without moving money into losing investments
You are very correct, rebalancing is basically selling off winners to buy losers. Of course the thinking is that selling a winner that has already increased 100% on the basis that it has doubled so it is likely to go down in the near future. However, just look at Apple as an example, if you bought Apple in June 2009 for $20 (adjusted price) and sold it as part of rebalancing when it rose to $40 (adjusted price) in September 2010, you would have missed out on it reaching over $95 2 years later. Similarly you look to rebalance by buying assets which have been battered (say dropped by 50%) on the basis that it has dropped so much that it should start increasing in the near future. But many times the price can fall even further. A better method would be to sell your winners when they stop being winners (i.e. their uptrend ends) and replace them with assets that are just starting their winning ways (i.e. their downtrend has ended and are now starting to Uptrend). This can be achieved by looking at price action and referring to the definitions of an uptrend and a downtrend. Definition of an uptrend - higher highs and higher lows. Definition of a downtrend - lower lows and lower highs. A strategy of rebalancing assumes that the business cycle will continue, that all bull and bear markets end eventually.  Imagine that you maintained a 50% split between a US Treasury bond mutual fund (VUSTX) and an S&P 500 stock mutual fund (VFINX) beginning with a $10,000 investment in each on January 1, 2008, then on the first of each year you rebalanced your portfolio on the first of January (we can pretend the markets are open that day). The following table illustrates the values in each of those funds with the rebalancing transactions: This second table shows what that same money would look like without any rebalancing over those years: Obviously this is cherry-picking for the biggest drop we've recently experienced, but even if you skipped 2008 and 2009, the increase for a rebalanced portfolio from 2010-2017 is 85% verses 54% for the portfolio that is not being rebalanced in the same period. This is also a plenty conservative portfolio. You can see that a 100% stock portfolio dropped 40% in 2008, but the combined portfolio only dropped 18%. A 100% stock portfolio has gained 175% since 2009, compared to 105% for the balanced portfolio, but it's common to trade gains for safety as you get closer to retirement. You didn't ask about a 100% stock portfolio in your initial question. These results would be repeated in many other portfolio allocations because some asset classes outperform others one year, then underperform the next. You sell after the years it outperforms, then you buy after years that it underperforms. Also, almost by definition rebalancing involves making more trades   than you would have otherwise; wouldn't the additional trading fees   you incurred in doing so reduce the benefits of this strategy? You forgot to mention taxes. Rebalancing does or rather can incur costs. One way to minimize the costs is to use the parts of the portfolio that have essentially zero cost of moving. These generally are the funds in your retirement accounts. In the United States they can be in IRAs or 401Ks; they can be regular or Roth. Selling winners withing the structure of the plan doesn't trigger capital gains taxes, and many have funds within them that have zero loads.  Another way to reduce trading fees is to only rebalance once a year or once every two years; or by setting a limit on how far out of balance. For example don't rebalance at 61/39 to get back to 60/40 even if it has been two years.  Given that the ratio of investments is often rather arbitrary to begin   with, how do I know whether I'm selling high and buying low or just   obstinately sticking with a losing asset ratio? The ratio used in an example or in an article may be arbitrary, but your desired ratio isn't arbitrary. You selected the ratio of your investments based on several criteria: your age, your time horizon, your goals for the money, how comfortable you are with risk. As these change during your investing career those ratios would also morph. But they aren't arbitrary.  These decisions to rebalance are separate from the ones to sell a particular investment. You could sell Computer Company X because of how it is performing, and buy stock in Technology Company Y because you think it has a better chance of growing. That transaction would not be a re-balancing. Selling part of your stock in Domestic Company A to buy stock in international Company B would be part of a re-balancing. If you are making regular periodic investments (e.g. each pay period into a 401(k) plan) or via automatic investment scheme in a non-tax-deferred portfolio (e.g. every month, $200 goes automatically from your checking account to your broker or mutual fund house), then one way of rebalancing (over a period of time) is to direct your investment differently into the various accounts you have, with more going into the pile that needs bringing up, and less into the pile that is too high. That way, you can avoid capital gains or losses etc in doing the selling-off of assets. You do, of course, take longer to achieve the balance that you seek, but you do get some of the benefits of dollar-cost averaging.
What you're describing is called timing the market.  That is, if you correctly predict when the market will drop, you can sell before the drop, wait for the drop, then buy after the drop has occurred.  Sell high, buy low. The fundamental problem with that, though, is: What ends up happening, on average, is you end up slightly behind.  There's quite a lot of literature on this; see Betterment's explanation for example.  Forbes (click through ad first) also has a detailed piece on the matter. Now, we're not really talking HFT issues here; and there are some structural things that some argue you can take advantage of (restrictions on some organizational investors, for example, similar to a blackjack dealer who has to hit on 16).  However, everyone else knows about these too - so it's hard to gain much of an edge. Plenty of people say they can time the market right, and even yourself perhaps you timed a particular drop accurately.  This tends to lead to false confidence though; how many drops that you timed badly do you remember? Ultimately, most investors end up slightly down when they attempt to time the market, because of the transaction costs (if you guess two drops, one 'right' and one 'wrong', and they have exactly opposite gains/losses before commissions, you will lose a bit on each due to commission), and because of the overall upward trend in the market (ie, if you picked at random one month a year to be out of the market, you'd lose around 10% annualized gains from doing that; same applies here). All of that aside, there is one major caveat: risk tolerance.  If you are highly risk tolerant, say a 30 year old investing your 401(k), then you should stay in no matter what.  If you're not - say you're 58 and retiring in a few years - then knowledge that there's a higher risk time period coming up might suggest moving to a less risky portfolio, even at the known cost of some gains. For a non-technical investor (meaning someone who doesn't try to do all the various technical analysis things that theoretically point to specific investments or trends), having a diverse portfolio and rebalancing it periodically will typically be the best solution. For example, I might have a long-term-growth portfolio that is 40% broad stock market fund, 40% (large) industry specific market funds, and 20% bond funds.  If the market as a whole tanks, then I might end up in a situation where my funds are invested 30% market 35% industry 35% bonds.  Okay, sell those bonds (which are presumably high) and put that into the market (which is presumably low).  Now back to 40/40/20.   Then when the market goes up we may end up at 50/40/10, say, in which case we sell some of the broad market fund and buy some bond funds, back to 40/40/20.  Ultimately ending up always selling high (whatever is currently overperforming the other two) and buying low (whatever is underperforming).   Having the industry specific fund(s) means I can balance a bit between different sectors - maybe the healthcare industry takes a beating for a while, so that goes low, and I can sell some of my tech industry fund and buy that.   None of this depends on timing anything; you can rebalance maybe twice a year, not worrying about where the market is at that exact time, and definitely not targeting a correction specifically.  You just analyze your situation and adjust to make everything back in line with what you want. This isn't guaranteed to succeed (any more than any other strategy is), of course, and has some risk, particularly if you rebalance in the middle of a major correction (so you end up buying something that goes down more).  But for long-term investments, it should be fairly sound. Note that if 1)  The stock prices are continuously differentiable (they aren't) 2)  You rebalance continuously in the absence of trading fees and taxes then the return fraction (future price / original price) will be the geometric mean of the return fractions for each investment. If you don't rebalance then the return fraction will be the arithmetic mean. But the arithmetic mean is ALWAYS greater than or equal to the geometric mean, so continuous rebalancing in the case of continuously differentiable prices will always hurt you, even abscent trading costs/taxes. Any argument in favor of blind rebalancing which does not somehow fail in the continuously differentiable case is simply wrong. See https://dl.dropboxusercontent.com/u/38536036/to%20karim.pdf -JT I think you're missing Simon Moore's point. His point is that, due to low inflation, the returns on almost all asset classes should be less than they have been historically, so we shouldn't rebalance our portfolio or withdraw from the market and hold cash based on the assumption that stocks (or any other asset) seem to be underperforming relative to historical trends.  His last paragraph is written in case someone might misunderstand him, he is not advocating to hold cash, just that investors should not expect as good returns as has happened historically, since those happened in higher inflation environments. To explain: If the inflation rate historically has been 5% and now it's 2%, and the risk-free-market return should be about 2%, then historically the return on a risk-free asset would be 7% (2%+5%), and now it should be expected to be 4% (2%+2%). So, if you have had a portfolio over some time you might be concerned that the rate of return is worsening, but Simon's point is that before you sell off your stocks / switch investment brokers, you should try to figure out if inflation is the cause of the performance loss. On the subject  of cash: cash always loses value over time from inflation, since inflation is a measure of the increase in prices over time-- it's a part of the definition of what inflation is.  That said, cash holdings lose value more slowly when inflation is lower, so they are relatively less worse than before. The future value of cash doesn't go up in low inflation (you'd need deflation for that), it just decreases at a lower rate, that is, it becomes less expensive to hold- but there still is a price. As an addendum, unless a completely new economic paradigm is adopted by world leaders, we will always see cash holdings decrease in value over time, since modern economics holds that deflation is one of the worst things that can happen to an economy. Determine an investment strategy and that will likely answer this for you. Different people have different approaches and you need to determine for yourself what buy and sell criteria you want to have. Again, depending on the strategy there can be a wide range here as some may trade index funds though this can backfire in some cases. In others, there can be a lot of buy and hold if one finds an index fund to hold forever which depending on the strategy is possible. Returns can vary widely as an index can be everything from buying gold stocks in Russia to investing in short-term Treasuries as there are many different indices as any given market can have an index which could be stocks, bonds, a combination of the two or something else in some cases so please consider asset allocation, types of accounts, risk tolerance and time horizon in making decisions or consider using a financial planner to assist in drawing up a plan with allocations and how frequently you want to rebalance as my suggestion here. "I'm assuming that all the savings are of 'defined contribution' type, and not 'defined benefit' as per marktristan's comment to the original question. Aside from convenience of having all the pension money in one place, which may or may not be something you care about, there may be a benefit associated with being able to rebalance your portfolio when you need do. Say you invest your pension pot in a 60%/40% of equities and bonds respectively. Due higher risk/reward ratio of the equities part, in the long run equities tend to get 'overweight' turning your mix into 70%/30% or even 80%/20%, therefore raising your overall exposure to equities. General practice is to rebalance your portfolio every now and then, in this case, by selling some equities and buying more bonds (""sell high, buy low""). Now if you have few small pockets of pension money, it makes it harder to keep track of the overall asset allocation and actually do the rebalancing as you cannot see and trade everything from one place." You have to understand what risk is and how much risk you want to take on, and weight your portfolio accordingly.  I think your 80/20 split based on wrong assumptions is the wrong way to look at it.  It sounds like your risk appetite has changed. Risk is deviation from expected, so risk is not bad, and you can have cases where everyone would prefer the riskier asset.   If you think the roulette table is too risky, instead of betting $1, stick 50c in your pocket and you changed the payoffs from $2 or 0 to 50c or $1.50 If your risk appetite has changed - change your risk exposure.  If not, then all you are saying is I bought the wrong stuff earlier, now I should get out. You can only lose your 7%. The idea that a certain security is more volatile than others in your portfolio does not mean that you can lose more than the value of the investment. The one exception is that a short position has unlimited downside, but i dont think there are any straight short mutual funds. I think the advice Bob is being given is good. Bob shouldn't sell his investments just because their price has gone down. Selling cheap is almost never a good idea. In fact, he should do the opposite: When his investments become cheaper, he should buy more of them, or at least hold on to them. Always remember this rule: Buy low, sell high. This might sound illogical at first, why would someone keep an investment that is losing value? Well, the truth is that Bob doesn't lose or gain any money until he sells. If he holds on to his investments, eventually their value will raise again and offset any temporary losses. But if he sells as soon as his investments go down, he makes the temporary losses permanent. If Bob expects his investments to keep going down in the future, naturally he feels tempted to sell them. But a true investor doesn't try to anticipate what the market will do. Trying to anticipate market fluctuations is speculating, not investing. Quoting Benjamin Graham: The most realistic distinction between the investor and the speculator is found in their attitude toward stock-market movements. The speculator's primary interest lies in anticipating and profiting from market fluctuations. The investor's primary interest lies in acquiring and holding suitable securities at suitable prices. Market movements are important to him in a practical sense, because they alternately create low price levels at which he would be wise to buy and high price levels at which he certainly should refrain from buying and probably would be wise to sell. Assuming that the fund in question is well-managed, I would refrain from selling it until it goes up again. "If the stock market dropped 30%-40% next month, providing you with a rare opportunity to buy stocks at a deep discount, wouldn't you want to have some of your assets in investments other than stocks? If you don't otherwise have piles of new cash to throw into the market when it significantly tanks, then having some of your portfolio invested elsewhere will enable you to back up the proverbial truck and load up on more stocks while they are on sale. I'm not advocating active market timing. Rather, the way that long-term investors capitalize on such opportunities is by choosing a portfolio asset allocation that includes some percentage of safer assets (e.g. cash, short term bonds, etc.), permitting the investor to rebalance the portfolio periodically back to target allocations (e.g. 80% stocks, 20% bonds.) When rebalancing would have you buy stocks, it's usually because they are on sale. Similarly, when rebalancing would have you sell stocks, it's usually because they are overpriced. So, don't consider ""safer investments"" strictly as a way to reduce your risk. Rather, they can give you the means to take advantage of market drops, rather than just riding it out when you are already 100% invested in stocks. I could say a lot more about diversification and risk reduction, but there are plenty of other great questions on the site that you can look through instead." "The calculation and theory are explained in the other answers, but it should be pointed out that the video is the equivalent of watching a magic trick.  The secret is: ""Stock A and B are perfectly negatively correlated.""  The video glasses over that fact that without that fact the risk doesn't drop to zero. The rule is that true diversification does decrease risk. That is why you are advised to spread year investments across small-cap, large-cap, bonds, international, commodities, real estate. Getting two S&P 500 indexes isn't diversification.  Your mix of investments will still have risk, because return and risk are backward calculations, not a guarantee of future performance. Changes that were not anticipated will change future performance. What kind of changes: technology, outsourcing, currency, political, scandal." When the market moves significantly, you should rebalance your investments to maintain the diversification ratios you have selected. That means if bonds go up and stocks go down, you sell bonds and buy stocks (to some degree), and vice versa. Sell high to buy low, and remember that over the long run most things regress to the mean. In your entire question, the only time you mention that this is an investment inside an IRA is when you say Every quarter, six months, whatever Id have to rebalance my IRA while Vanguard would do this for the fund of funds without me needing to. Within an IRA, there are no tax implications to the rebalancing. But if this investment were not inside an IRA, then the rebalancing done by you will have tax implications. In particular, any gains realized when you sell shares in one fund and buy shares in another fund during the rebalancing process are subject to income tax. Similarly, losses also might be realized (and will affect your taxes). However, if you are invested in a fund of funds, there are no capital gains (or capital losses) when re-balancing is done; you have gains or losses only when you sell shares of the fund of funds for a price different than the price you paid for them. I do this very thing, but with asset allocation and risk parity in mind. I disagree with the cash or bust answers above, but many of the aforementioned facts are valuable and I don't mean to undermine them in anyway. That said, let's look at two examples: Option 1: All-in For the sake of argument let's say you had $100k invested in the SPY (S&P 500 ETF) in early 2007, and you kept it there until today. Your lowest balance would have been about $51k, and at this point the possibility of you losing your job was probably at a peak. Today you would be left with $170k assuming no withdrawal. Option 2: Risk Parity BUT if you balanced your investments with a risk parity approach, using negatively correlated asset classes you avoid this dilemma. If you had invested 50% in XLP (Consumer Staples Sector ETF) and 50% in TLT ( Long Term Treasury ETF) your investments low point would have been $88k, and your lowest annual return would be +0.69%. Today you would be left with $214k assuming no withdrawals.  I chose option #2 and it hasn't failed me yet, even in 2016 so far the results are steady and reliably given the reward. My general opinion is simple: when you have money always grow it. Just be sure to cover your ass and prepare for rain. Backtesting for this was done at portfoliovisualizer.com, the one caveat to this approach is that inflation and a lack of international exposure are a risk here. If so, it seems to me that this system is rather error prone. By that I mean I could easily forget to make a wire some day and be charged interests while I actually have more than enough money on the check account to pay the debt. I have my back account (i.e. chequing account) and VISA account at/from the same bank (which, in my case, is the Royal Bank of Canada). I asked my bank to set up an automatic transfer, so that they automatically pay off my whole VISA balance every month, on time, by taking the money from my bank account. In that way I am never late paying the VISA so I never pay interest charges. IOW I use the VISA like a debit card; the difference is that it's accepted at some places where a debit card isn't (e.g. online, and for car rentals), and that the money is deducted from my bank account at the end of the month instead of immediately.