To rebalance or not to rebalance
"An asset allocation formula is useful because it provides a way to manage risk. Rebalancing preserves your asset allocation. The investment risk of a well-diversified portfolio (with a few ETFs or mutual funds in there to get a wide range of stocks, bonds, and international exposure) is mostly proportional to the asset class distribution. If you started out with half-stocks and half-bonds, and stocks surged 100% over the past few years while bonds have stayed flat, then you may be left with (say) 66% stocks and 33% bonds. Your portfolio is now more vulnerable to future stock market drops (the risk associated with stocks). (Most asset allocation recommendations are a little more specific than a stock/bond split, but I'm sure you can get the idea.) Rebalancing can be profitable because it's a formulaic way to enforce you to ""buy low, sell high"". Massive recessions notwithstanding, usually not everything in your portfolio will rise and fall at the same time, and some are actually negatively correlated (that's one idea behind diversification, anyway). If your stocks have surged, chances are that bonds are cheaper. This doesn't always work (repeatedly transferring money from bonds into stocks while the market was falling in 2008-2009 could have lost you even more money). Also, if you rebalance frequently, you might incur expenses from the trading (depending on what sort of financial instrument you're holding). It may be more effective to simply channel new money into the sector that you're light on, and limit the major rebalancing of the portfolio so that it's just an occasional thing. Talk to your financial adviser. :)" "'Buy and Hold' Is Still a Winner: An investor who used index funds and stayed the course could have earned satisfactory returns even during the first decade of the 21st century. by By Burton G. Malkiel in The Wall Street Journal on November 18, 2010: ""The other useful technique is ""rebalancing,"" keeping the portfolio asset allocation consistent with the investor's risk tolerance. For example, suppose an investor was most comfortable choosing an initial allocation of 60% equities, 40% bonds. As stock and bond prices change, these proportions will change as well. Rebalancing involves selling some of the asset class whose share is above the desired allocation and putting the money into the other asset class. From 1996 through 1999, annually rebalancing such a portfolio improved its return by 1 and 1/3 percentage points per year versus a strategy of making no changes."" Mr. Malkiel is a professor of economics at Princeton University. This op-ed was adapted from the upcoming 10th edition of his book ""A Random Walk Down Wall Street,"" out in December by W.W. Norton. http://online.wsj.com/article/SB10001424052748703848204575608623469465624.html" "Rebalancing is, simply, a way of making sure your risk/reward level is where you want it to be. Let's say you've decided that your optimal mix is 50% stocks and 50% bonds (or 50% US stocks, 50% international, or 30/30/30 US large-cap/US small-cap/US midcap...).  So you buy $100 of each, but over time, the prices will of course fluctuate.  At the end of the year, the odds that the ratio of the value of your investments is equal to the starting ratio is nil.  So you rebalance to get your target mix again. Rebalance too often and you end up paying a lot in transaction fees.  Rebalance not often enough and you end up running outsize risk. People who tell you that you should rebalance to make money, or use ""dollar cost averaging"" or think there is any upside to rebalancing outside of risk management are making assumptions about the market (mean regressing or some such thing) that generally you should avoid." "In theory, investing is not gambling because the expected outcome is not random; people are expecting positive returns, on average, with some relationship to risk undertaken and economic reality. (More risk = more returns.) Historically this is true on average, that assets have positive returns, and riskier assets have higher returns. Also it's true that stock market gains roughly track economic growth. Valuation (current price level relative to ""fundamentals"") matters - reversion to the mean does exist over a long enough time. Given a 7-10 year horizon, a lot of the variance in ending price level can be explained by valuation at the start of the period. On average over time, business profits have to vary around a curve that's related to the overall economy, and equity prices should reflect business profits. The shorter the horizon, the more random noise. Even 1 year is pretty short in this respect. Bubbles do exist, as do irrational panics, and milder forms of each. Investing is not like a coin flip because the current total number of heads and tails (current valuation) does affect the probability of future outcomes. That said, it's pretty hard to predict the timing, or the specific stocks that will do well, etc. Rebalancing gives you an objective, automated, unemotional way to take advantage of all the noise around the long-term trend. Rather than trying to use judgment to identify when to get in and out, with rebalancing (and dollar cost averaging) you guarantee getting in a bit more when things are lower, and getting out a bit more when things are higher. You can make money from prices bouncing around even if they end up going nowhere and even if you can't predict the bouncing. Here are a couple old posts from my blog that talk about this a little more:" This answer will assume you know more math than most. An ideal case: For the point of argument, first consider the following admittedly incorrect assumptions: 1)  The prices of all assets in your investment universe are continuously differentiable functions of time. 2)  Investor R (for rebalance) continuously buys and sells in order to maintain a constant proportion of each of several investments in his portfolio. 3)  Investor P (for passive) starts with the same portfolio as R, but neither buys nor sells Then under the assumptions of no taxes or trading costs, it is a mathematical theorem that investor P's portfolio return fraction will be the weighted arithmetic mean of the return fractions of all the individual investments, whereas investor R will obtain the weighted geometric mean of the return fractions of the individual investments. It's also a theorem that the weighted arithmetic mean is ALWAYS greater than or equal to the weighted geometric mean, so regardless of what happens in the market (given the above assumptions) the passive investor P does at least as well as the rebalancing investor R.  P will do even better if taxes and trading costs are factored in. The real world:  Of course prices aren't continuously differentiable or even continuous, nor can you continuously trade.  (Indeed, under such assumptions the optimal investing strategy would be to sample the prices sufficiently rapidly to capture the derivatives and then to move all your assets to the stock increasing at the highest relative rate.  This crazy momentum trading would explosively destabilize the market and cause the assumptions to break.) The point of this is not to argue for or against rebalancing, but to point out that any argument for rebalancing which continues to hold under the above ideal assumptions is bogus.  (Many such arguments do.)  If a stockbroker standing to profit from commission pushes rebalancing on you with an argument that still holds under the above assumptions then he is profiting off of BS. Yes E[x] is expected value of x. E[x|y] = expected value of x, given y. c, k are some constants Let E[s_{n+1}|s_n=c] = c, but if  E[s_{n+1}|s_n,s_{n-1},...,s_{n-m}] ->some constant k as m->\infty (call this equation 1) then rebalancing makes sense. Notes:
"Split your contributions evenly across the funds on that list with the word ""core"" or ""S&P"" in the name.  Maybe add ""International Large Cap Index"".  Leave it & rebalance occasionally.  Read a book on Modern Portfolio Theory sometime in the next 5 years." Sure, but as a retail client you'd be incurring transaction fees on entry and exit. Do you have the necessary tools to manage all the corporate actions, too? And index rebalances?   ETF managers add value by taking away the monstrous web of clerical work associated with managing a portfolio of, at times, hundreds of different names. With this comes the value of institutional brokerage commissions, data licenses, etc. I think if you were to work out the actual brokerage cost, as well as the time you'd have to spend doing it yourself, you'd find that just buying the ETF is far cheaper.  Also a bit of a rabbit hole, but how would you (with traditional retail client tools) even coordinate the simultaneous purchase of all 500 components of something like SPY? I would guess that, on average, you're going to have significantly worse slippage to the index than a typical ETF provider. Add that into your calculation too. Rebalance is across asset-classes which are mutually independent [like stocks and bonds; they may be inversely correlated at times as when stocks go down, bonds go up] 80%-20% (stock-bond) split is good for a young investor [say in 30s, some suggest 110-age as a good stock allocation percentage]. Here rebalance is done when say the asset-allocation(AA) strays away more than say 3 to 5% (again just a rule of thumb). E.g. if due to a recent run-up in stocks, AA could become 85%-15%. Then you sell stocks to buy bonds to make the AA 80%-20% And since this method always sells the winner -- you automatically make gains [selling high and buying low] S&P 500 index gives decent diversification within stocks; you want a total-bond-fund to take care of the bond side of your AA. "The diversification offered by the advisor can easily be duplicated at Vanguard with something like the Ivy Portfolio. Simplify it or complicate it to your liking, with Vanguard index REITs, index stock funds, international, bond, etc. Set up automatic contributions and don't watch your money like a hawk. Set it and forget it, or maybe rebalance your holdings once a year. The main thing advisors are good for (at your level of assets) is persuading investors to stay in the market during a crash. Most investors will sell after a crash, and completely miss out on the rebound. It's human nature to be a terrible market timer. But if you can really promise yourself never to sell in a panic, then you don't need an advisor at your asset level. Fees like ""1.25%"" sound like a okay deal but should be viewed in context. With an average annual return of, say, 7%, a 1.25% fee represents nearly 18% of your gain for the year. And 1.25% may be the least of your fees - what about fees when you get out of the funds? (Neat trick, huh, calling a fee ""1.25%"" instead of ""~18%""..). Is active management worth 18% of your yearly gain? Your advisor's fee and the active funds' fees compound year after year, because they take the fees out of your account every year (or month)." R has really good package that lets you calculate the return of rebalanced portfolios. The package is called: PerformanceAnalytics (see: http://www.inside-r.org/packages/cran/PerformanceAnalytics/docs/Return.portfolio). I quickly wrote a small script for you that lets you do exactly what you want.  Code: By default the portfolio is rebalanced to an equally weighted portfolio. It is also possible to rebalance your portfolio using custom weights. See the documentation on how to do this.  In order for this code to work you need to have your data already in return terms. You can do this easily in Excel. Make sure your data in excel looks like this: Than export your data to a CSV file. Note: before you run the code make sure you have installed the package PerformanceAnalytics. You can do this as follows:  Let me know if you have any questions regarding the above. 0.13% is a pretty low fee.  PTTRX expenses are 0.45%, VINIX expenses are 0.04%. So based on your allocation, you end up with at least 0.08%. While lower than 0.13%, don't know if it is worth the trouble (and potentially fees) of monthly re-balancing. As has been said before, going from nothing to something is an infinite percent increase! It is not 100%. Maybe you had a dollar and now have $101 that is a 10000% increase! Quite remarkable. I often work with symmetrized percent changes like: spc = 100 * (y2-y1)/(0.5 * (y1+y2)) Where I compute the percent with respect to the average. First this is more stable as often measurements can have noise, the average is more reliable.  Second advantage is also that this is symmetric. So going from 95 to 105 is a 10 % increase while going from 105 to 95 a 10% decrease. Of course you need to explain what you show. I still don't see the point of this software; rebalancing frequently is a waste of money (through fees).  If you invest in index funds, you don't have to rebalance at all--effectively, the fund is doing it for you, and since they can generally trade more efficiently than individual investors can, that's a win.  The Coverdell ESA is a great example.  There's a maximum contribution amount, just as there are for almost any tax-exempt account.  A decent financial adviser could help you plan how much to contribute to which accounts, at what time, and when you can/should start to withdraw from them.