The S&P 500 Is Priced for 2% Returns. Is Your Retirement Built for That?

The S&P 500 has hit 23 all-time highs in 2026. Your 401(k) balance probably looks good. That feeling is worth examining.

Beneath the record closes sits a number that has only appeared once in 140 years of market data. The Shiller CAPE ratio — which measures stock prices against 10-year average inflation-adjusted earnings — stood at 40.88 in June 2026, according to data tracked by GuruFocus. The only prior instance was December 1999, when the ratio peaked at 44.19 before the S&P 500 fell 49% over the following two and a half years. Before that, the highest readings were around 32 in 1929, and 27 heading into the 2008 financial crisis. At 40.88, the current market is priced for an optimism that has an extremely thin historical precedent.

A Number Most Retirement Plans Don’t Know About

The CAPE ratio is not a market-timing tool. It will not tell you when the correction comes, or whether it comes at all before you retire. What it does is something more practically useful: it predicts the range of returns you can reasonably expect over the next decade, based on what followed every prior reading this elevated in 140 years of history.

The answer at a CAPE of 40.88 is not 7%. Analysis from HeyGoTrade found that the CAPE earnings yield — the simple inverse of the ratio — currently sits at approximately 2.4%. That figure represents the real annual yield from corporate earnings at today's prices, assuming flat growth. Research compiled by Michael Kitces at Kitces.com confirms the pattern: equities at current valuation levels have historically delivered roughly 5.5% nominal returns over the subsequent 30-year period — about one percentage point less than the historical baseline most retirement projections assume. The more aggressive CAPE-based forecasts put the next decade's real returns in the low single digits, consistent with what followed every prior CAPE reading above 30.

This is not a prediction. It is a probability statement derived from the longest market dataset available. And most retirement calculators are not making it.

The 7% Assumption Is Doing the Heavy Lifting in Your Plan

Open almost any retirement calculator and the default annual return field reads 7%. Some say 8%. Occasionally 6%. These figures come from long-run S&P 500 historical averages, and as historical facts they are accurate. But those averages include many decades where the CAPE ratio started below 10, 12, 15 — the low valuations where 10%-plus growth years became possible. Nobody runs a 30-year retirement projection from a CAPE of 9 today. They are running it from 40.88.

The Kitces analysis on CAPE-adjusted assumptions found that starting from today's valuations should reduce your expected real equity return by approximately one percentage point relative to the historical average. That sounds small. Run it through a retirement model over 30 years and it is not.

What This Means in Your Retirement Calculator

Here is the scenario that makes this tangible.

Assume you are 35 years old, with $50,000 already saved. You contribute $600 a month and plan to retire at 65 needing $1.5 million. At 7% annual returns, you reach approximately $1.65 million — on track, with margin. Drop the assumption to 5%, closer to what CAPE-adjusted research suggests is realistic, and you arrive at roughly $1.1 million — $550,000 short of your target. At 4%, the midpoint between the CAPE earnings yield and the Kitces-adjusted baseline, you land near $890,000. Nearly $600,000 short of what your plan requires.

The Retirement Calculator runs this in under a minute. Enter your current age, balance, monthly contribution, target nest egg, and expected return. Then run it three times: at 7%, at 5%, and at 4%. The gap between those three outputs is the number your current retirement plan is not accounting for.

If the 4% scenario leaves you short, there are exactly two levers: retire later, or contribute more each month. The calculator shows you which combination closes the gap at your current savings rate. That is a decision worth making at 35, not at 63.

The Compounding Gap Is Bigger Than You Think

The retirement calculator shows you the endpoint. The Compound Interest Calculator shows you the machinery underneath it — and how profoundly the return rate shapes what that machinery produces.

Model $500 per month in contributions for 30 years at 7%: your terminal value is approximately $566,000. At 4%, that same contribution schedule delivers roughly $347,000. At 2% — the actual CAPE earnings yield at current market prices — the result is approximately $246,000.

The gap between the 7% scenario and the 2% scenario on identical monthly contributions over 30 years is roughly $320,000. That is not a rounding error. It is the difference between retiring on schedule and working an additional decade.

What Most People Get Wrong About Valuations This High

Two mistakes happen most often when the CAPE gets this elevated.

The first: investors confuse the stock market performing well with their retirement plan performing well. The S&P 500 returning 15% in a year when inflation is 4% is an 11% real gain — impressive. But the next decade's real return is not decided by last year. It is determined, in large part, by the price you paid for the earnings. At a CAPE of 40.88, you are paying one of the highest prices in history per dollar of corporate earnings. That price does not vanish because the index keeps going up.

The second mistake is treating the CAPE ratio as a crash predictor and dismissing it when the crash doesn’t arrive on schedule. The Motley Fool recently noted that CAPE crossed 30 years before the dot-com peak — and investors who acted on that signal in 1997 missed three more years of gains before the correction. The CAPE does not tell you when to exit. It tells you how much trust to place in the return assumption embedded in your retirement projections. Elevated or not, the market rewards those who stay in it. Through bull runs and valuation extremes, the discipline to keep contributing has historically outperformed the discipline to wait.

Time in the market remains the stronger bet. The investors who held through every CAPE warning over the past three decades did not outperform by predicting corrections. They outperformed because they kept contributing. The lesson from an elevated CAPE is not to stop investing — it is to make sure the number in the return field reflects what the evidence says is probable rather than what feels comfortable.

The One Change That Actually Fixes This

Drop the return assumption in your retirement plan from 7% to 5%. Run the numbers. If you are still on track, you have margin you did not know you had. If you are not, you know the gap now — before the market delivers that information on its own terms.

The adjustment is rarely catastrophic. For most people, $100 to $200 more per month closes most gaps when combined with one extra working year. The investors who will be blindsided by low-return outcomes are the ones who never ran the scenario.

Your retirement plan does not come with a CAPE ratio warning. The return field defaults to whatever you typed in. That is your job — to type in something the data supports.