Even the simplest financial plan requires assumptions about how your investments will perform. We know these assumptions can never be perfectly accurate, but they need to be thoughtful and reasonable. If you’re just assuming a balanced portfolio will return 7% every year, then your projections aren’t likely to be useful.
So what exactly are reasonable assumptions for stocks and bonds? In Great Expectations—a new white paper I’ve co-authored with Raymond Kerzérho, PWL Capital’s director of research—we explain the methodology we use when creating financial plans.
There are two main approaches one can use when estimating future returns. The first is to rely on history: for example, if the average return of global stocks over the last century was 8%, one could simply assume the same going forward. The second approach uses valuation metrics to estimate future stock returns based on current market conditions. You can also apply these two methods to expected bond returns, using either the long-term historical average or the current yield on a benchmark index.
As you’ve probably figured out, both methods are flawed. But as we argue in the white paper,