by Adam Nash on December 31, 2010

One of the prudent financial housekeeping chores that people face every year is rebalancing their portfolio. Over the course of the year, some investments outperform, and others underperform.  As a result, the allocation that you so carefully planned at the beginning of the year has likely shifted.  If left unmanaged over the years, individuals can end up with profoundly more risk or worse performance than expected.

Rebalancing your portfolio annually tries to address this issue by forcing you to sell asset classes that outperformed in the previous year, and purchase those that underperformed.  In practice, I try to rebalance the week before New Years as a way of cleaning up going into the next year.  While most academic research points to rebalancing as healthy every one to three years, I find that annual rebalancing provides the following benefits:

• Forces you to see how your investments performed for the year
• Forces you to learn which asset classes actually did well during the year, and which didnt
• Forces you to re-assess the appropriate asset mix for your risk tolerance and financial situation
• Forces you to revisit which investments you are using to represent each asset class (mutual funds, ETFs, individual securities, etc)
• Forces you to actively engagement with your portfolio, and reset your balance to the appropriate mix

Ive just completed my rebalancing for 2011, and I thought Id share some of the process here, in case its useful to anyone whose New Years Resolution is to be more proactive about their finances.

Rebalancing is actually a very simple process its kind of surprising that basic financial tools like Mint and Quicken dont actually help you do this.  Whether youve never rebalanced or your rebalance every year, there are fundamentally five steps:

1. Assess your current investment portfolio, broken down by types of assets
2. Calculate the percentage of your portfolio in each asset class
3. Calculate the difference in dollars for each asset class in your portfolio from your ideal mix
4. Finalize the list of investments you will use to represent each asset class
5. Make the trades necessary (buys and sells) to bring your portfolio into balance

This can all be done within an hour, with the exception of making the trades.  Those can spread over days, potentially, since certain types of securities (like mutual funds) take time to execute (typically 24 hours).

Step 1: Assess your current investment portfolio

Believe it or not, this can actually be the most time consuming part of the process, especially if you have accumulated accounts over the years and havent ever used any sort of tool like Quicken to pull your portfolio together accurately.

A few ground rules on how I think about portfolio allocation:

• Im a big believer in the research that shows that most of your long term investment return is based on asset mix. not security selection.  This means I do not spend time picking individual stocks. bonds, or dabble with active mutual funds in general.
• I use very broad definitions of asset classes .  For example:  US Stocks vs. International Stocks vs. Emerging Markets.   These tend to correlate with the standard definitions used broadly to define popular investment indexes. Technically, with sophisticated software and data, you can do very fine-grained breakdowns.  I dont bother with this, as the resulting differences are statistically marginal vs. the effort / complexity involved.

Fear not, because with tools like Microsoft Excel or Google Docs, this has become much, much easier.  All you need to do is:

• Make a spreadsheet with the following columns:  Security Name, Ticker, Shares, Share Price, Total Value, % of Total Portfolio
• Fill in a row for everything you own, regardless of account

The second part is very important, if you want to avoid the mental accounting that leads people to invest differently in one account versus another.  If youve worked at multiple companies, you may have multiple 401k, IRA, college savings accounts, and brokerage accounts in your name.   Obviously, reducing the number of accounts you have is helpful, but sometimes its unavoidable.  Maybe you have a Roth IRA, a regular IRA, and a 401(k) with your current employer.

This becomes important because certain accounts may have limited access to different types of investments.  For example, your Vanguard IRA might only let you buy Vanguard funds (not such a bad thing), while your 401(k) at work might limit you to some pretty meager options.  When we get to Step 5, we can take advantage of multiple accounts to get the right balance by buying the best investments in the accounts with the best access to them.

Here is an example screenshot of a simplified list of investments that I bet wouldnt be that unusual in Silicon Valley.  This person has some Vanguard index funds that they purchased prudently the last time they looked at their portfolio, combined with some stocks they purchased based on TechCrunch articles.  (I wish I were kidding).

You can see immediately that this small amount of accounting can actually help organize your thinking about what you own, and force you to remember why you own it.

Notice, I do not recommend putting in columns showing how well an investment performed historically.  For rebalancing, you only care about the here and now.  The past is just that the past.  Performance data will likely just add emotion to a decision that, when made best, should be purely analytical.

Step 2: Calculate the percentage of your portfolio in each asset class

The hardest part about this step is defining what you are going to use as an asset class.   There is no one right answer here Ive seen financial planners break down assets into literally dozens of classes.  Ive also seen recommendations that literally only use two (stocks vs. bonds).

The great thing about asset classes is that you can always break down an existing bucket into sub-buckets.

For example, if you decide to have 30% of your money in bonds, and 70% in stocks, you can then easily make a 2nd level decision to split your stock money into 50% US and 50% international.  You can then make a third level decision to split the international money 2/3 for developed markets, and 1/3 for emerging markets.  In fact, for some people, this is a much easier way to make these decisions.  Do whatever works for you, but be consistent about it.

Personally, Ive gotten quite a bit of mileage using the following break downs:

US Stocks

Large Cap

Mid Cap

Small Cap

International Stocks

Developed Markets

Emerging Markets

Standard

Inflation Protected

You can see in the screenshot above, calculating these buckets is fairly simple.  You just total up each group, and then divide it into the portfolio total.  So in the example I provided, the individual has 11.5% of their money in fixed income.

As the size of your assets increase, more sophisticated breakdowns are likely warranted.  But for the purposes of this blog post, I think you get the idea.

With mutual funds, this can be tricky.  For example, did you know that the Vanguard Total Market fund is 70% Large Cap, 21% Mid Cap, and 9% Small Cap?  (I got this data off etfdb.com ).  In order to solve this problem, I actually create a separate column for each asset class.  I then put the percentage for each fund in each column, totaling to 100%.  I then multiply those percentages by the amount invested in each fund, giving me an actual dollar amount per asset class.

Step 3: Calculate the difference in dollars for each asset class in your portfolio from your ideal mix

This is the step where your self-assessment turns toward action.  How far are you off plan.

The hardest problem here is the implied problem: what is your ideal mix?

There are quite a few rules of thumb out there, and more than enough magazines and books out there to tell you what this should be.  Unfortunately, all of them are over-simplified, and none of them likely apply exactly to you.  At minimum, its a whole separate blog post to come up with this.  Fortunately, if you pick up the 2011 planning issue from Smart Money, Kiplingers, or Money magazine, youll probably end up OK.

But lets say our individual in question is a 30-year old engineer who believes in the rule of thumb that they should take 120 minus their age, put that in stocks and the remainder in bonds.  Lets say also that theyve read that their stock investments should be split 50/50 between the US & International, with at least 10% of their overall portfolio in Emerging Markets.

That would leave our hypothetical engineer with the following breakdown:

• 90% in Stocks

45% US Stocks

35% Developed Markets

10% Emerging Markets

Based on the numbers from the first screenshot, they would create an spreadsheet table like this:

This shows that our hypothetical engineer needs to rebalance by selling US Stocks, Emerging Markets, and Bonds.  The extra money will be re-allocated to international stocks in developed markets.

Step 4: Finalize the list of investments you will use to represent each asset class

Most people skip this step, but thats a real missed opportunity.   Once you decide how much money to allocate to a given asset class, its worth a bit of thought about what is the best way to capture the returns of that asset class.  For example, is owning Google, Apple & Goldman Sachs the best way to capture the returns of US Stocks?  Im not a professional financial planner, so you shouldnt take my advice here.  But my guess is that youll be hard pressed to find a professional who believes that those three stocks represent a balanced portfolio.

We live in an unprecedented time.   Individuals with a few hundred dollars to invest can go to a company like E*Trade, open an account, and for $9.99 buy shares in an ETF that represents all publicly traded stocks in the US, for an annual expense of 7 basis points.  Thats 0.07%, or just $7 for every $10,000 invested.  That is an unbelievable financial triumph.  Previously, only multi-millionaires had access to that type of investment, and they paid a lot more for the privilege than 7 basis points.

Personally, Im heavily biased towards using these low cost, index based ETF shares to represent most asset classes.  In fact, E*Trade lets you mark any ETF for free dividend reinvestment under their DRIP functionality.  As a result, you get all the benefits of mutual funds with lower annual costs!  It takes some research to find the best ETFs, and in some cases, standard no-load mutual funds are a better option.  (Once again, Im not a professional, so do your own research on what secrurities make sense for you.)

The biggest exception to this is with 401(k) plans, where you have limited choices on what types of investments you can make.  In these cases, I evaluate all of the funds in the 401(k), find those that are best in class, and purposely unbalance the 401(k) to invest in those.  I then make up for that lack of balance with my investments outside the 401(k).  For example, lets say your current 401(k) has excellent international funds, but poor US funds.   you can skew your 401(k) to international funds, and make your US investments outside of the 401(k) where there are better options.

For our hypothetical engineer, lets say that hes decided to stick with Series I Savings Bonds for his fixed income, and uses the Vanguard ETFs to represent the different stock classes.

Step 5: Make the trades necessary (buys and sells) to bring your portfolio into balance

It seems like this part should be simple, but it can be surprising how many complications arise.  For example:

• Sometimes the model says to sell $112 of something.  The trading costs alone make that likely prohibitive and unlikely to be worthwhile.
• Share prices change every day, and your model leaves you short a few dollars here and there.
• The model doesnt take into account commissions for trading
• Some funds have fees
• Some transactions have tax consequences
• Some investments can only be purchased in one account, not another
• Some investments cannot be bought in a given account (like a 401k)

As a result, there is no advice that will apply to everyone.  Taxes alone make this the time when you may have to consult a professional.

In our hypothetical case, our engineer would:

• Sell their stakes in Apple, Google, Goldman Sachs, and Teva
• Decide to leave their Series I Bonds alone not worth the trouble.  Take the extra money out of the developed markets stake.
• Purchase / Sell shares in the Total Market, Ex-US, and Emerging Market ETFs to meet their new allocation goals

The following table shows how to use a spreadsheet to calculate the different trades (buys in Green, sales in Red):

Last Thoughts

Ive been doing some version of the process above for at least fifteen years at this point, and its never failed to help me with my financial planning.  Of all the benefits described, annual rebalancing gives me the confidence to withstand the day-to-day gyrations of the markets, with the confidence that at the end of the year, Ill get a shot to rebalance things.

There are a few temptations that Ive noticed could lead someone astray:

• Changing the ideal asset mix year-to-year based not on financial research, but based on whats hot at the moment.  For example, if you find yourself saying that Gold should be 10% of your portfolio one year, and then the next year its Farmland, youve got some popular investing psychology drifting into your process.
• You pick arbitrary hot stocks to represent asset classes.  This can lead to a double-whammy, you not only pick a bad stock, but you also miss out on key gains in your selected asset class.
• Splitting hairs.  Dont stress about small dollar amounts, or potentially, asset classes when your portfolio is small.  I remember investing the first $2500 I ever made from a summer job, and I got a little carried away with the breakdown.  In general, you can get pretty far with just the Total Stock Market and Total Bond Market.

This was a really long blog post, but hopefully it will prove useful to those who are interesting in balancing their portfolios, or just curious on how other people do it.  In either case, please comment or email if you find mistakes, or have additional questions.   Happy to turn the comment section here into a useful discussion.