S&P 500 CAPE ratio at 41.85, a level only the dot-com era has beaten

The S&P 500 CAPE ratio, the valuation gauge that compares the index against ten years of inflation-adjusted earnings, stood at 41.85 at the close on Monday, October 12. That is a level no equity market has touched since the 1999-2000 dot-com era, where the record 44.19 reading of December 1999 sits, and it is the number behind the roughly 20,000 searches for "s&p 500 cape ratio history" this week.

The ratio, also called the Shiller PE or cyclically adjusted price-to-earnings ratio, computes the S&P 500's price relative to average real earnings over the past decade, a span long enough to wash out a single business cycle. multpl.com publishes it daily using the dataset compiled by Nobel laureate Robert Shiller at Yale. Averaging ten years of earnings smooths the peaks and troughs that distort a conventional price-to-earnings ratio, which is why investors watch CAPE when the question is whether stocks are expensive in a way that history would recognize.

Related reading: VIX Explained: What 14.84 Says About Stocks Before CPI.

By that measure, the answer is a clear yes, and it is big. Only three stretches since 1871 have pushed CAPE above 32: the run into the 1929 crash at 32.6, the 1999 bubble at 44.2, and now at 41.85. Multicap contributor analysis at gate.com notes that this is only the third time the index has topped that threshold in 156 years, and it points out that the S&P 500 has delivered about a 21 percent annualized return over the past four years against a 100-year average near 10 percent. Periods of unusually high returns, the same analysis cautions, have typically preceded sharp declines as valuations mean-revert.

The honest caveat is that CAPE is a long-horizon lens, not a market-timing signal, and the 2.3-point gap between today's print and the 1999 record tells nobody when an adjustment comes. Shiller himself built the measure to flag long-run expected returns, not to call a top; valuations can stay elevated for years while earnings grow into them, and a forward earnings surge is exactly how the current reading could be carried higher from here. The comparison that matters is 41.85 against the 17.42 average since 1871, a roughly 2.4 times premium that has been matched only once before.

Related reading: S&P 500 Sits Near a Record With Only 26% of Stocks Above Their 50-Day Average: The Capped-Breadth Rally.

Who does it reach? Index-fund holders, retirement savers, and anyone deciding whether this year's rally has gotten ahead of the numbers. The metric updates with every close, so the next meaningful print comes the same day the index does, near Monday's 7,807.24 finish. This week the September CPI report lands Oct. 14 at 12:30 UTC, and the Federal Reserve's Oct. 27-28 meeting follows with the index already sitting at a valuation milestone. The jump in search interest reflects people asking whether this rally has outrun the numbers, and the next close will refresh the answer.

Related reading: Regional bank stocks rebound into CPI: KRE gains 0.80%.

Related reading: Microsoft stock jumps 2% to $533 as an AI and Azure rally returns.

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