Some Thoughts on “Dollar Cost Averaging”

Photo by: Rob Lee

The term “Dollar Cost Averaging”, or DCA, can have many different meanings.  Oftentimes when referring to “Dollar Cost Averaging,” people actually mean “Automatic Investing.”  DCA typically refers to investing over a period of time an amount you could have invested initially.  So for example, if you had $10,000 to invest, instead of putting it all in now, you invest it over a period of several months in equal dollar amount increments.  Automatic Investing on the other hand is simply taking a set amount out of your income and investing it every month.  This is what the majority of people think of as Dollar Cost Averaging.

The Theory

Proponents of DCA claim that it reduces risk, because you tend to buy more shares when prices are low and fewer shares when prices are high.  This argument makes some sense in an oscillating market that isn’t moving overall in any particular direction.  One question remains, however: why would you want to be investing in an oscillating market that isn’t trending in one direction?  Typically most people’s faith in investing in stock markets is that over time they go up.  If the market is on average going to move upwards, why am I holding back investing a portion of my investment?  On average this simply means I’m going to get a higher price.

The Worst-Case Scenario

If we think about this matter anecdotally it seems intuitive however that by holding back some money to invest we’re reducing our worst-case scenario.  Suppose for example that we invest all our money today and tomorrow the stock drops precipitously.  We’ve avoided that risk.  At the same time however, what if the stock rises sharply and never returns to our original price.  While we may be reducing our worst-case scenario somewhat, we’re also risking leaving a lot of money on the table.  Still there seems to be some merit to increasing your exposure over time.

In Practice

In reality the way most of us “Dollar Cost Average” is that we invest a certain amount each month out of our paycheck into the stock market.  This is what is more accurately referred to as “Automatic Investing,” and is sort of a no-brainer.  However if you do receive an influx of funds and are trying to decide what to do with them, Dollar Cost Averaging may not be all it’s cracked up to be.  There can be psychological advantages to moving your money in over time, but transaction fees can add up quickly, depending on how your brokerage charges.  Think carefully before assuming Dollar Cost Averaging is right in all situations.