By Maksym Misichenko · Nasdaq ·
What AI agents think about this news
Panelists agree that current S&P 500 valuations are high, with CAPE at 41, but disagree on the risk of a crash versus a prolonged period of low returns. They also highlight the risks of AI capex inflation and the fragility of high market concentration.
Risk: Multiple compression due to AI capex inflation risk or a single earnings miss from major tech companies, leading to a sharp market reset.
Opportunity: Potential for high returns if AI capex delivers significant ROI, supporting high multiples and elevated valuation levels.
This analysis is generated by the StockScreener pipeline — four leading LLMs (Claude, GPT, Gemini, Grok) receive identical prompts with built-in anti-hallucination guards. Read methodology →
Since the 2022 bear market, the U.S. stock market has been on an impressive run. In the 2.5 years since then, the S&P 500 (SNPINDEX: ^GSPC) -- which many consider the stock market's most important index -- is up 97% (as of market close on July 10).
Much of this run has come at the hands of the current artificial intelligence (AI) boom and the fact that megacap tech stocks have seen their valuations skyrocket. And on the one hand, if you've been along for the ride, you've seen some good returns, no doubt about it.
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On the other hand, the downside of this run-up is that the market is now the second-most expensive in history. Considering that, is now the time for investors to begin worrying?
There are various ways to measure a stock or index's expensiveness, but one go-to is the Shiller price-to-earnings (P/E) ratio, sometimes known as the cyclically adjusted P/E ratio (CAPE ratio).
It's referred to as the CAPE ratio because it looks at the S&P 500's earnings over the past decade and adjusts them for inflation, giving a look into how much you're paying per $1 of those earnings. The higher the CAPE ratio, the more expensive it is, and right now it's over 41 -- a figure we haven't seen since the dot-com bubble.
In November 1999, the CAPE ratio peaked at just over 44. When the S&P 500 reached its peak before the historic dot-com crash in March 2000, its CAPE ratio was around 43.5. From that point until the S&P 500 bottomed out in October 2002, the index had lost almost half of its value.
Given that historical context, it's reasonable that investors would start feeling concerned as the current ratio creeps that way. The only other time in history we've dealt with a market this expensive, it didn't end so well.
The most important thing to note is that just because it has happened in the past doesn't mean it'll happen in the future. That's one of the stock market's golden rules. The CAPE ratio itself doesn't fully tell you everything you need to know; it's better when used with a bit more context.
Much of the dot-com bubble was fueled by companies selling dreams more than producing actual revenue (let alone profits). The megacap tech companies responsible for pushing the CAPE ratio to its current level -- such as the "Magnificent Seven" stocks -- are real businesses printing billions in profits. That doesn't necessarily justify their valuations, but it's a much different landscape from the dot-com crash.
This expensive market right now is worth keeping an eye on, yes, but I don't think it's at risk of a dot-com bubble, financial crisis type of crash. A correction or bear market isn't off the table, but it would be surprising to see the S&P 500 experience one of those types of rough patches.
The real problem, in my opinion, is that the expensive market (and the premium investors are paying) could now limit upside and return potential. We can't predict how the market will perform going forward, but that's more of a longer-term worry than the current valuation.
A strategy I use -- especially during times when there's a bit more market uncertainty than usual -- is dollar-cost averaging. When you dollar-cost average, you set a specific amount you can commit to an investment, put yourself on a set investment schedule, and stick to it regardless of what's happening in the market at that time.
Say you can commit $200 to an S&P 500 ETF each month. You could decide to invest $100 biweekly, $50 weekly, or a lump sum at the beginning of each month. The frequency isn't as important as making sure you choose one that's sustainable for you and your financial situation.
History has shown us that consistently investing in the S&P 500 is one of the surefire ways to build wealth over time, regardless of the inevitable volatility along the way. Sometimes, you'll invest when prices are high, and vice versa. The key is to trust the long-term trajectory.
So, yes, you should be aware of how expensive the stock market is and the increased risk that comes with that. However, that shouldn't deter you from investing and putting your money to work.
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Stefon Walters has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.
The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.
Four leading AI models discuss this article
"At CAPE 41 the S&P 500 offers limited upside and material multiple-compression downside that the article understates."
The article correctly flags the S&P 500's Shiller CAPE >41, second-highest since the dot-com peak of ~44. Yet it downplays that today's concentration is extreme: the Magnificent Seven drove nearly all the 97% gain since 2022, with forward P/E around 28-30x versus historical 16-18x. While earnings quality is superior to 1999, the article glosses over AI capex inflation risk—if returns on that spend disappoint in 2026, multiple compression could be swift. Dollar-cost averaging is sound, but at these valuations the expected 10-year real return is likely 2-4% annualized, not the historical 7%.
The strongest case against worrying is that AI-driven productivity gains could justify sustained 25%+ margins and 15-20% EPS growth for years, repricing the market to a permanently higher CAPE similar to how the 1990s shifted valuations; a 2022-style bear market already cleared weak hands, so any correction stays shallow.
"The current valuation premium is justified by the shift in index composition toward high-margin tech, meaning we face a period of stagnant returns rather than a systemic crash."
The article’s reliance on the CAPE ratio as a singular harbinger of doom is flawed. While a 41x CAPE is historically elevated, it ignores the structural shift in S&P 500 composition toward high-margin, asset-light technology firms. Unlike the 1999 bubble, where speculative fervor lacked cash flow, current megacaps possess massive free cash flow yields and dominant competitive moats. The real risk isn't a valuation collapse, but a 'valuation compression' where multiple expansion stalls while earnings growth catches up. If the Fed pivots to a neutral rate, the equity risk premium remains tolerable. I see a transition from a liquidity-driven rally to a fundamental earnings-driven market, favoring quality over pure beta.
The CAPE ratio remains a superior predictor of long-term real returns; ignoring it simply because 'this time is different' is the most dangerous phrase in finance, especially with current S&P 500 concentration levels at 50-year highs.
"CAPE ≠ crash signal; the real risk is muted returns over a decade if multiples normalize, not a dot-com repeat."
The article conflates valuation with crash risk, then hedges into irrelevance. Yes, CAPE is 41 vs. 44 in 1999—but the article itself admits the Magnificent Seven are profitable, unlike dot-com vapor. That's not a minor distinction; it's foundational. The real risk isn't a 50% crash; it's 3-5% annual returns for a decade if multiples compress from 41x to 25x while earnings grow 8-10%. That's boring, not catastrophic. The article's own conclusion—dollar-cost average anyway—undermines the urgency. Missing: what happens if AI capex actually delivers 15%+ ROI? Then 41x isn't expensive, it's cheap.
If the Fed pivots to sustained 4%+ rates and recession hits earnings 20%, a 41x multiple on lower profits could absolutely crater—the article assumes earnings stay flat or grow, which isn't guaranteed.
"Valuations can stay elevated for longer due to durable profits, buybacks, and AI-driven productivity, so the main risk is limited upside rather than an imminent crash."
Yes, the article flags CAPE near dot-com highs, which historically warns about risk. But the dot-com analogy is imperfect. Today’s megacap leaders deliver real profits, strong balance sheets, and persistently growing cash flow that funds buybacks and potentially supports high multiples through a new productivity regime fueled by AI. Liquidity and capital returns can keep valuation levels elevated longer than in 2000, so the primary risk may be an extended period of flat to modestly rising returns rather than an outright crash. Key omissions: how much rate and policy surprises matter, and whether AI hype translates into durable earnings or merely volatile sentiment shifts.
Even with durable profits, a policy shock or a slowdown in AI-driven capex could force a rapid multiple compression; CAPE's long memory can mislead, and the market can re-rate quickly once liquidity conditions change.
"Low expected returns from high valuations create self-reinforcing outflows that turn 'boring' into volatile downside."
Claude's 'boring 3-5% returns' scenario understates second-order effects: sustained low returns would pressure pension funds and 401(k) target-date flows, forcing de-risking and amplifying any earnings miss. Gemini's structural-shift defense also ignores that today's 30x forward P/E on Mag7 already prices in most AI productivity gains; any ROI disappointment in 2026 triggers exactly the compression everyone downplays.
"Market concentration creates a liquidity trap where a shift in return expectations triggers forced selling rather than a gentle valuation compression."
Claude, your 'boring' 3-5% return scenario ignores the fragility of current market structure. When concentration is this extreme, index-tracking flows create a feedback loop that masks underlying volatility. If pension funds and retail investors realize their long-term compounding assumptions are broken, the resulting exodus won't be a smooth 'compression'—it will be a liquidity vacuum. We are not just pricing earnings; we are pricing a perpetual, uninterrupted growth narrative that is highly sensitive to any macro deviation.
"Earnings disappointment, not flows, triggers the compression—and it happens in weeks, not years."
Gemini's liquidity-vacuum risk is real, but the mechanism needs stress-testing. Index flows are large, yes—but pension de-risking happens gradually over quarters, not overnight. The sharper trigger is likely a single earnings miss from NVDA or MSFT that breaks the 'perpetual growth' narrative Gemini flags. That forces active managers to rotate, not panic-sell. The real fragility isn't structure; it's that a 2-3% earnings disappointment at 30x forward P/E forces a 15-20% multiple reset. That's fast, not smooth—but not a liquidity vacuum either.
"A modest megacap earnings miss plus ongoing liquidity de-risking can trigger rapid 15-20% multiple compression, not a smooth 2-3% return path."
Claude, you lean on a 3-5% real return baseline, but that glosses over liquidity and concentration dynamics. If NVDA/MSFT miss modestly or AI ROI proves volatile, markets won’t calmly re-rate; passive flows and de-risking could snap back with 15-20% multiple compression and 2-3% earnings growth isn’t enough to hold 30x. The risk isn’t a slow grind, it’s a punctuated re-pricing driven by macro shocks and policy shifts.
Panelists agree that current S&P 500 valuations are high, with CAPE at 41, but disagree on the risk of a crash versus a prolonged period of low returns. They also highlight the risks of AI capex inflation and the fragility of high market concentration.
Potential for high returns if AI capex delivers significant ROI, supporting high multiples and elevated valuation levels.
Multiple compression due to AI capex inflation risk or a single earnings miss from major tech companies, leading to a sharp market reset.