Lazy Portfolio

A lazy portfolio is a do-it-yourself portfolio built to need almost no ongoing decisions: a handful of broad, cheap index funds, held at target percentages chosen once, and brought back to those percentages at set intervals. What makes it lazy is the absence of judgment calls after the initial design. There is no forecasting of markets, no choosing of individual securities, and no changing the mix in response to news. The term is an informal one that comes from investor communities and personal finance writing rather than from any regulator or standards body, so two people describing "a lazy portfolio" may be describing quite different mixes.

The family has a small number of named recipes, and the differences between them are narrower than the debates about them suggest. Scott Burns, whose Dallas Morning News column began in 1991, described a Couch Potato portfolio of two index funds, one tracking the S&P 500 and one tracking a broad US bond index, split evenly. The three-fund portfolio, named in the Bogleheads community, adds international stocks as a third holding. Others cut the same markets into more slices by adding small-cap, value, real estate or inflation-protected bond funds. Every version is doing the same thing: buying the market rather than picking within it, and deciding the stock-and-bond balance in advance.

Because the recipes share their design, the arguments between them are about second-order questions. How much international exposure, whether to tilt toward small or value companies, whether to hold real assets separately. Those choices matter, but they matter far less than the two decisions every version makes identically: the overall stock-and-bond split, and the commitment not to change it in response to markets. An investor choosing between a three-fund and a seven-fund lazy portfolio is choosing between two answers that will behave similarly. An investor choosing between 80 percent stocks and 40 percent stocks is choosing between two different lives.

The word "lazy" carries a risk worth naming, because it describes the wrong attribute. A portfolio that is 100 percent in a total stock market index fund and rebalanced never is maximally lazy and can fall by half. Low maintenance and low risk are unrelated properties, and the name only speaks to the first. The design decision that determines what the portfolio will do to its owner is the asset allocation, which the lazy structure requires but does not supply.

There is also a boundary with the packaged version. A target-date fund carries out the same discipline inside a single holding, and adds an automatic shift toward bonds over time that a fixed-weight lazy portfolio does not have. The trade is control and cost against convenience: a lazy portfolio is usually cheaper and lets the owner hold different assets in different account types for tax reasons, while a target-date fund cannot be split that way and does not need anyone to remember to rebalance.

Building one is three decisions and one recurring task.

1. Choose the asset allocation. How much in stocks, how much in bonds, how much in cash. This is decided from time horizon, financial ability to absorb a loss, and willingness to sit through one, and it is the decision that determines the portfolio's behavior.
2. Choose the funds. Broad, cheap, and as non-overlapping as possible. Fewer funds means fewer places for a mistake to hide and less to rebalance.
3. Write the targets down, along with the rebalancing rule: a date, a drift threshold such as five percentage points, or both.
4. Rebalance on the rule, not on the news.

A hypothetical example of the recurring task. Elena starts the year with $100,000 at targets of 60 percent US stocks, 20 percent international stocks and 20 percent bonds, so $60,000, $20,000 and $20,000. Over the year US stocks return 20 percent, international returns 5 percent and bonds return 2 percent. The sleeves become $72,000, $21,000 and $20,400, and the portfolio is worth $113,400.

The new targets are 60 percent of $113,400, or $68,040, and 20 percent each, or $22,680. So the rebalance sells $3,960 of the US fund and buys $1,680 of international and $2,280 of bonds. Note that the arithmetic forces Elena to sell the holding that just returned 20 percent and buy the one that returned 2 percent. That is the entire discipline, and it is the reason a written rule exists: the transaction is obvious on paper and uncomfortable in practice.

In a taxable account the same rebalance realizes a capital gain on the $3,960 sold, so many investors direct new contributions toward the underweight holdings first and only sell when contributions cannot close the gap.

Pros

• Very low cost, because broad index funds are the cheapest way to own a market and there is almost no trading.
• Very low time commitment, and low enough complexity that a spouse or executor can understand the portfolio without help.
• Removes the two decisions that do the most damage, which securities to pick and when to be in the market, by never making them.
• Assets can be placed in different account types for tax reasons, which a single packaged fund cannot do.

Cons

• The fixed weights do not change as the owner ages, so a lazy portfolio does nothing on its own about a shortening time horizon.
• The name invites the belief that the portfolio is safe. It is only as conservative as the allocation it was given.
• Rebalancing requires selling winners, which is the part people skip, and a lazy portfolio that is never rebalanced drifts into whatever has grown most.
• There is no authoritative definition, so published lazy portfolios differ from one another and comparisons between them are not like-for-like.
• Rebalancing in a taxable account has a tax cost the packaged alternative handles internally.