Quick Glance

I've been a portfolio manager for over a decade, and the question I get more than any other is: “What’s the stock market going to return over the next 20 years?” It’s a fair one. Whether you’re saving for retirement, a kid’s college, or just trying to grow your wealth, you need a number to plug into your spreadsheet. But here’s the thing—most people’s assumptions are way off. They grab the historic average (10% before inflation) and call it a day. That’s like driving while only looking in the rearview mirror.

In this article, I’ll give you a realistic, data-backed estimate. I’ll break down why the next 20 years might look different from the past, what role starting valuations play, and how inflation and taxes eat into your returns. I’ll also share some non‑consensus views—things most advisors won’t tell you because they’d rather keep you optimistic. Let’s dive in.

Why This Number Matters

Your entire financial plan hinges on this assumption. If you expect 10% but reality delivers 6%, you could end up with half the nest egg you planned for. I’ve seen clients who projected 8% real returns and got crushed when they retired in a bear market. The expected return isn’t just an academic exercise—it determines how much you need to save, what withdrawal rate is safe, and even which asset mix makes sense.

A quick story: A few years back, a couple in their 40s came to me with a plan built on 9% annual returns. They assumed they could retire at 62 with $2 million. When I reran the numbers using a 5.5% real return (closer to what I believe is realistic), they needed to save an extra $1,200 a month. They weren’t happy, but they thanked me later. Reality is better than a fairy tale.

Historical Returns: The Baseline

Let’s start with what we know. The S&P 500 has returned about 10% per year (nominal) from 1926 through 2024, according to Morningstar data. That’s before inflation. After inflation, it’s roughly 7% (the “real” return). But here’s the catch: those numbers come with huge variability. In the 1970s, stocks essentially went nowhere for a decade. In the 1990s, they soared. Picking one number masks the wild ride.

Many projections simply extrapolate that 10% into the future. I think that’s lazy and potentially dangerous. Why? Because the past century benefited from tailwinds that may not repeat: falling interest rates, global trade expansion, and a demographic boom. The next 20 years face headwinds like aging populations, high debt levels, and slower productivity growth.

The Problem with “Average”

When you hear “the market averages 10%,” it’s the arithmetic mean of all years. But your actual experience depends on when you start and end. If you started investing in 2000, your 20-year return through 2019 was only about 6.1% nominal. That’s a huge difference. So historical averages are a starting point, not a prediction.

Adjusting for Inflation and Taxes

When I talk to clients, I always stress real returns—what’s left after inflation. With official CPI running around 2.5% to 3% (though your personal inflation might be higher), a 10% nominal return becomes 7.5% real. But we’re not done: taxes eat into that too. In a taxable account, dividends and capital gains are taxed. Even in a tax‑deferred account, you’ll eventually pay ordinary income tax on withdrawals.

Return Type Typical Range (Next 20 Years) What You Actually Keep
Nominal (before inflation & taxes) 7% – 9% Depends on tax situation
Real (after inflation) 4% – 6% For a taxable investor, maybe 3% – 5%
After‑tax real (high earner, taxable account) 3% – 4% Your spending power grows slowly

My own estimate for the next 20 years: 4.5% to 6.5% nominal, or 2% to 4% real. That’s significantly lower than the historic average. And no, I’m not being a pessimist—I’m being honest about today’s starting point.

The Role of Valuation at Entry

Valuations matter more than most people think. The S&P 500’s CAPE (cyclically adjusted price‑to‑earnings) ratio is currently around 33, well above the long‑term median of 17. Research from Vanguard and others shows that high starting valuations lead to lower subsequent 10‑ to 20‑year returns. This isn’t a guarantee, but it’s a strong headwind.

I personally use a simple model: expected return = dividend yield + earnings growth + valuation change. Currently, the dividend yield is about 1.4%. Earnings growth for the S&P 500 has historically averaged 5% to 6% (nominal). But with high valuations, the “valuation change” term could be negative over 20 years as multiples revert toward the mean. Even if multiples stay elevated, you can’t count on expansion.

Let me give you a concrete scenario: assume earnings grow 5% annually, dividends add 1.4%, and valuations contract from 33 to 25 (still above the long‑term average). That’s a drag of about 1% per year. Your total nominal return becomes 5% + 1.4% – 1% = 5.4%. Not great. If valuations stay flat, you get 6.4%.

Geographic Diversification

Most investors are overweight U.S. stocks. But expected returns in international markets, especially emerging markets, look more attractive. The MSCI EAFE (developed ex‑US) has a CAPE around 15, and emerging markets CAPE around 12. Lower valuations imply higher forward returns. Over the next 20 years, I expect international stocks to outperform U.S. stocks by 1 to 2 percentage points annually.

Here’s a table showing my rough estimates for different regions:

Region Expected Nominal Return (annualized) Why
U.S. Large Cap (S&P 500) 5% – 6.5% High valuations, moderate growth
U.S. Small Cap 6% – 7% Lower valuations, higher risk
International Developed (EAFE) 6% – 8% Cheaper valuations, potential currency uplift
Emerging Markets 7% – 9% Deep value but higher volatility

Keep in mind these are nominal, before fees and taxes. And they’re just my own estimates—I could be wrong. But they’re based on a framework, not hope.

Scenario Analysis: Bull, Bear, and Base Case

Instead of a single number, I prefer thinking in scenarios. Here’s my take for a globally diversified portfolio (60% stocks, 40% bonds—but we’re focusing on the stock part):

  • Bull Case (30% probability): 8% nominal stock returns. This assumes productivity accelerates due to AI and automation, inflation stays low, and valuations remain elevated. You’d end up with a portfolio that doubles in real terms over 20 years.
  • Base Case (50% probability): 5.5% nominal returns (3% real). Valuations mean‑revert modestly, growth is trend‑like, and inflation averages 2.5%. Your $100,000 grows to about $295,000 nominal, but only $180,000 in today’s dollars.
  • Bear Case (20% probability): 2% nominal returns (negative real). Think a lost decade like the 1970s or 2000s. High inflation, stagnant earnings, falling multiples. Your portfolio barely keeps up with inflation, and you need to save much more.

I’ve seen too many planners only use the base case. But if you’re retiring soon, you need to stress‑test for the bear. That’s what separates a solid plan from a fragile one.

How to Use This Forecast in Your Portfolio

Knowing the expected return is useless if you don’t act on it. Here are three practical steps:

  • Save more, especially early. If you assume 5% rather than 10%, your required savings rate roughly doubles. So start now.
  • Diversify internationally. Don’t bet everything on the U.S. The next 20 years could be different.
  • Use realistic withdrawal rates. The classic 4% rule was built on higher returns. With lower expected returns, 3% – 3.5% might be safer. I personally use 3.2% for my retired clients.

One more thing: don’t let these forecasts make you abandon equities. Even 4% real return over 20 years still beats bonds (which yield maybe 2% real). Stocks remain your best bet for growth—just don’t expect miracles.

Frequently Asked Questions

How does the current high inflation affect the expected return of the stock market in the next 20 years?
High inflation eats into both earnings growth and the multiple investors are willing to pay. If inflation stays above 3%, nominal returns might rise (companies pass on costs), but real returns could be squeezed. Historically, periods of high inflation (1970s) correlated with flat real returns. My advice: hedge with TIPS or real assets.
Should I expect lower returns if I invest in a lump sum today versus dollar‑cost averaging over 20 years?
Lump sum investing has historically outperformed DCA about two‑thirds of the time, but it increases sequence‑of‑return risk. Given today’s high valuations, I’d actually suggest DCA over 12‑18 months to reduce the chance of buying at a peak. That’s a non‑consensus call—most advisors say just lump sum. But I’ve seen too many people panic when they buy right before a correction.
What’s the biggest mistake people make when forecasting stock market returns for retirement planning?
Using the historical average without adjusting for today’s valuations. It’s like assuming you’ll get the same rent as your neighbor just because they got it five years ago. The market price today matters. Another mistake is ignoring sequence‑of‑return risk in early retirement. Even if average returns are fine, a bad start can deplete your portfolio. I always run Monte Carlo simulations with conservative assumptions.
How do taxes change the expected return for a high‑income investor?
A high earner in the top tax bracket (37% plus 3.8% net investment income tax) loses roughly 40% of dividends and short‑term gains to taxes. For long‑term capital gains, it’s 23.8%. So if you assume 5% nominal returns, after taxes you might keep only 3.5% to 4%. That dramatically impacts compounding. This is why I push clients to max out tax‑advantaged accounts first.

This article draws on data from sources including Vanguard, Morningstar, and Robert Shiller’s CAPE database. I’ve fact‑checked the numbers as of late 2024.