Historical Returns vs Future Expectations

Historical Returns vs Future Expectations

When planning for financial independence, you'll inevitably face a question: what investment returns should you assume? Historical data is the obvious starting point, but the past doesn't guarantee the future. Here's how to think about calibrating your expectations.

What History Shows

The S&P 500 has delivered roughly 10% average annual returns over the long term. Looking at data from 1928 through 2024, the average annual return has been about 10% nominally. The last 20 years showed returns around 11% annually, while the last 10 years came in around 14.7% (through October 2025), boosted by strong recent performance.

But those nominal numbers overstate your actual purchasing power growth. After adjusting for inflation, the real compound annual growth rate drops to approximately 6.9%. That's the number that matters for maintaining your lifestyle over a multi-decade retirement.

Why the Future Might Differ

Several factors could make future returns higher or lower than historical averages. Current market valuations matter: when stocks are expensive relative to earnings, subsequent returns tend to be lower. Interest rates, which have been historically unusual in recent decades, affect both bond returns and stock valuations.

Demographic changes, global economic shifts, and technological disruption could push returns in either direction. The honest answer is that we don't know what future returns will be. Anyone claiming certainty is selling something.

The 2025 Context

The S&P 500 delivered strong returns in 2025 (around 17.9% including dividends), continuing a bull market that started in October 2022. Since that bull market began, cumulative returns exceeded 100% by year-end 2025. But such strong recent performance doesn't predict future returns. If anything, periods of above-average returns are often followed by periods of below-average returns (regression to the mean).

Practical Implications for FIRE Planning

Most financial planners suggest assuming 6-7% real returns for long-term planning. This accounts for historical performance while leaving room for the possibility of lower future returns. It's a balance between being realistic enough that your plan works and conservative enough that you're not caught off guard.

For FIRE specifically, your assumption should match your risk tolerance and flexibility. If you're retiring early with little room for error, assume the lower end of reasonable expectations. If you have flexibility (ability to return to work, spending you could cut, other income sources), you can assume slightly higher returns.

Running Scenarios

Rather than picking one "correct" return assumption, run your FIRE calculations with several scenarios: optimistic (8-9% real), moderate (6-7% real), and conservative (4-5% real). See how your plan holds up across these ranges. A plan that only works in the optimistic scenario is too fragile. A plan that works even in the conservative scenario gives you margin.

Use history as a guide, not a guarantee. Plan for a range of possible futures, not just the one you hope for.