New Here? Get the Free Newsletter

Oblivious Investor offers a free newsletter providing tips on low-maintenance investing, tax planning, and retirement planning. Join over 21,000 email subscribers:

Articles are published Monday and Friday. You can unsubscribe at any time.

Why Do Risk-Adjusted Returns Matter?

A reader writes in, asking:

“Why do academics always talk about risk adjusted returns? I get that risk matters and you shouldn’t have a riskier portfolio than you can manage. But if I compare two strategies over a period, I’m better off at the end if I used the strategy with the higher return, not the one with the higher risk adjusted return. So why is risk adjusted return relevant?”

The usefulness of the risk-adjusted return concept is that we can use it to evaluate a proposed strategy to determine whether it has historically been a better way to increase returns (or reduce risk) than simply adjusting any of several other well known variables (e.g., stock vs. bond allocation, duration of bond holdings, credit quality of bond holdings, etc.).

For example, imagine that you currently have a 50% stock, 50% bond portfolio that uses simple “total market” index funds for both the stock and bond portions. But then you meet with a financial advisor who suggests that you would be better off if you got rid of your total market stock funds and switched to a portfolio of individual stocks, picked according to a specific set of criteria. And this advisor shows you historical data demonstrating that his hand-picked stock portfolio has had higher returns over the last several years than your total market stock funds.

Obviously, one problem here is the critically dubious implication that the past is a good predictor of the future. But let’s set that aside for the moment to focus on another problem: A portfolio comprised of a handful of individual stocks will generally have far more risk than a broadly diversified total market stock portfolio.

In other words, the advisor isn’t making an apples-to-apples comparison, and he has not demonstrated that his strategy is actually an improvement over a total market strategy. What needs to be demonstrated is whether the 50% bond, 50% hand-picked-stock portfolio the advisor is proposing has had greater returns than an index fund portfolio with the same level of risk.

For example, you might find that the advisor’s 50/50 strategy with handpicked stocks has historically had a risk profile comparable to a 70/30 stock/bond portfolio using total market funds but that its historical annualized return is closer to that of a 60/40 portfolio using total market funds. If that’s the case, then the advisor has clearly not added any value. All he has done is bump up the risk and return in an inefficient way. A 70/30 total market portfolio would have had higher returns with the same level of risk as what the advisor is proposing, and a 60/40 total market portfolio would have had the same level of returns, with less risk than what the advisor is proposing.

New to Investing? See My Related Book:

Book6FrontCoverTiltedBlue

Investing Made Simple: Investing in Index Funds Explained in 100 Pages or Less

Topics Covered in the Book:
  • Asset Allocation: Why it's so important, and how to determine your own,
  • How to to pick winning mutual funds,
  • Roth IRA vs. traditional IRA vs. 401(k),
  • Click here to see the full list.

A Testimonial:

"A wonderful book that tells its readers, with simple logical explanations, our Boglehead Philosophy for successful investing." - Taylor Larimore, author of The Bogleheads' Guide to Investing
Disclaimer: By using this site, you explicitly agree to its Terms of Use and agree not to hold Simple Subjects, LLC or any of its members liable in any way for damages arising from decisions you make based on the information made available on this site. I am not a financial or investment advisor, and the information on this site is for informational and entertainment purposes only and does not constitute financial advice.

Copyright 2019 Simple Subjects, LLC - All rights reserved. To be clear: This means that, aside from small quotations, the material on this site may not be republished elsewhere without my express permission. Terms of Use and Privacy Policy

My new Social Security calculator (beta): Open Social Security