Where today's market sits against each measure's own history — on two bases, each month ranked only against the months before it.
The values are today's data. CAPE and earnings yield revise little, and only in their recent months, so that makes little difference. The Buffett lens divides each day by the GDP published by that day, at its value then — first-published from Dec 1991; before that, today's revised GDP stepped forward on its release lag, since no earlier first prints are archived. The allocation lens’s history is the Fed's revised accounts: first prints exist only from 2019, and three of its expensive periods (1967, 2007 and 2019) appear only on data revised since.
Every lens reads at or near its most expensive — CAPE is higher than 99% of its own history, and has been since December 2023.
Over the next year that has told you nothing on CAPE: its expensive periods returned more than the rest, not less; only the earnings-yield lens leaned, 24 of 33 below the rest. Over three years it has — expensive CAPE periods came in below the rest 16 times out of 20, and the earnings-yield lens 23 out of 30.
October's reading, like the months before it, can still move: multpl restates recent months as companies report their earnings, for months after they end, and the site takes each restatement the night it appears.
Ten years on. Every ten-year period that began from a cheap reading ended higher — 16 of 16. The 3 that ended lower all began from an expensive one: CAPE in 1930, and the Buffett lens twice in 1999.
The cheap end. CAPE and the household-allocation lens have not been at their cheap end since 1985; the Buffett and earnings-yield lenses were there in 2008–09.
What the record will and will not carry. The three-year finding rests on how often expensive periods came in below the rest, not on how often they lost money. The losing three-year windows are a handful of clustered events, and a rule built on them breaks when any one cluster is removed. At five years CAPE's gap does not survive dropping 2003–2007. And most of the longest lens predates the engines this was tested against, so those tests reach only its recent quarter.
What it does. It says how expensive the market is against its own history. Over a year it has said nothing on three of the four lenses. The earnings-yield lens leaned: its expensive periods came in below the rest 24 times out of 33. Over three it has tilted the odds. It has never said when.
Measured September 2026. The full record →
Paths are S&P total return · Shiller monthly convention (dividends reinvested monthly). Construction and fidelity pins: "The total-return basis" on the Confluence methodology. Historical record, not a forecast. How it's measured →