S&P 500 PE Ratio: Trailing Price-to-Earnings Series Since 1871 (Shiller Data)

The S&P 500 PE ratio measures the index price divided by reported earnings over the trailing 12 months — the most widely cited equity valuation metric since the 1930s. This long-term series, compiled by Robert Shiller from Yale University’s ie_data.xls dataset, extends the S&P 500 PE ratio back to 1871 by linking the modern S&P 500 reported-earnings series with the Cowles Commission’s reconstruction of US equity earnings for the pre-1926 period. Unlike the cyclically adjusted CAPE, the trailing PE responds directly to short-term earnings swings — making it useful for cycle context but mechanically distorted during recessions, when collapsing earnings inflate the ratio at the trough.

Dataset: S&P 500 Trailing P/E Ratio (1871–2026) · Updated 2026-07-01

Source: Robert Shiller, Yale University — ie_data.xls (Online Data, U.S. Stock Markets 1871–Present). Open academic data.

Macro Takeaway

Dataset Overview

Dataset Variables

The CSV and Excel files contain the following columns.

Column names match the CSV headers exactly.

Download the Complete Dataset

The full S&P 500 PE ratio dataset is available in CSV and Excel formats.

Direct CSV Access — Eco3min Structured Dataset

https://eco3min.fr/dataset/sp500-pe-ratio.csv

This URL returns the complete dataset in CSV format. It can be used directly in pandas, R, curl, or any data tool.

Using the Dataset in Python

import pandas as pd

url = "https://eco3min.fr/dataset/sp500-pe-ratio.csv"
df = pd.read_csv(url, parse_dates=["date"])

print(df.head())
print(df.describe())

Using the Dataset in R

library(readr)

url <- "https://eco3min.fr/dataset/sp500-pe-ratio.csv"
df <- read_csv(url)

head(df)
summary(df)

Both examples load the dataset directly from the URL — no download or API key required.

Methodology

The S&P 500 PE ratio is computed as the index level divided by the trailing 12-month sum of reported (GAAP) earnings per share. For the post-1957 period, Shiller uses Standard & Poor’s official S&P 500 reported-earnings series; for the pre-1926 segment, the calculation relies on the Cowles Commission reconstruction of US equity earnings, which Shiller links to the modern index for continuity. The intermediate 1926–1957 segment uses S&P Composite data published by Standard Statistics (the pre-1957 predecessor of S&P).

The underlying data is published in Robert Shiller’s ie_data.xls spreadsheet, updated monthly on his Yale Department of Economics page. Monthly observations are typically end-of-month, with earnings expressed as a trailing four-quarter sum. The series is not seasonally adjusted — both numerator (price) and denominator (annual sum of quarterly earnings) absorb seasonality directly.

Eco3min mirrors the Shiller dataset via an automated monthly pipeline that ingests ie_data.xls, validates the schema, and republishes the cleaned series in CSV and Excel formats with consistent column naming.

Data Quality & Provider Notes

The Shiller ie_data.xls file is the academic reference for long-term US equity valuation series. Reliability is high for post-1957 observations; pre-1957 figures inherit the Cowles Commission methodology and should be treated as reconstructions rather than directly observed market data.

• Release latency. Robert Shiller updates ie_data.xls at roughly monthly cadence, typically within the first half of each month for the previous month’s observation. Eco3min mirrors the file on a monthly pull aligned with Shiller’s update.
• Revisions policy. Recent observations may be revised when S&P 500 reported earnings are restated (quarterly 10-Q amendments, late filings, accounting corrections). Revisions further back than approximately two years are rare. Pre-1957 historical reconstructions are stable across releases.
• Alternative sources. The same underlying methodology is available through Bloomberg, Wharton Research Data Services (WRDS), and aggregators such as multpl.com (which republishes Shiller). Bloomberg’s PE_RATIO field defaults to operating earnings, producing a structurally lower number than Shiller’s reported-earnings series — the two are not directly comparable.
• Known gaps. Monthly cadence means no intra-month observation. Pre-1881 earnings figures are linearly interpolated by Shiller from sparse annual data; analytical caution is warranted for that segment.

Before running any time-series operation that assumes a specific end date, verifying the latest observation against Shiller’s source file is the recommended data-integrity step.

Common Pitfalls When Using the S&P 500 PE Ratio

The S&P 500 PE ratio is widely cited but several recurring interpretation errors distort the signal it carries.

1. Trailing PE vs forward PE. This series uses trailing 12-month realized earnings. Forward PE — built on consensus estimates for the next 12 months — is structurally lower at cycle peaks and higher at troughs because analysts revise estimates with a lag. Comparing a trailing PE level to a forward PE benchmark gives a systematically biased reading.
2. Reported (GAAP) vs operating earnings. Shiller’s series uses reported earnings, which include write-downs, impairments, and one-time charges. Operating-earnings PE (Bloomberg default, S&P’s “operating” series, FactSet ex-items) excludes these, producing a ratio that can sit two to five points lower during recessions when write-downs spike. Mixing the two in a comparison is a frequent error.
3. Counter-intuitive recession spikes. Because earnings collapse faster than prices at recession troughs, the trailing PE often peaks after a market bottom — the 2009 reading exceeded 100 when reported earnings were briefly near zero. Users often misread these spikes as “extreme overvaluation” when they are denominator artifacts of the trailing methodology.
4. Confusing this series with the Shiller CAPE (PE10). Both are authored by Robert Shiller from the same ie_data.xls file, but they measure different things. The S&P 500 PE ratio uses 12-month trailing earnings; the CAPE ratio uses a 10-year inflation-adjusted average of earnings. The CAPE smooths the cyclical noise the trailing PE captures — they are complementary, not interchangeable.

Historical Regimes

The S&P 500 PE ratio has cycled through several distinct valuation regimes since 1871, each shaped by the prevailing monetary, inflation, and corporate-margin backdrop.

1871–1920 — Pre-Fed low-PE baseline. Trailing PE generally oscillated between 10 and 18, with sharp drops during the major panics of 1873, 1893, and 1907, and during the 1917–1918 wartime shock. The absence of a central bank made monetary regimes mechanically tighter, and durable PE expansion was limited.

1929–1933 — Crash mechanics and denominator collapse. The September 1929 peak occurred at a trailing PE near 32. The subsequent 1932–1933 trough recorded paradoxically elevated readings (PE briefly exceeded 25 again) as reported earnings collapsed faster than the index — the canonical illustration of the recession-spike pitfall described above.

1949–1965 — Post-war re-rating. The trailing PE climbed from approximately 7 in 1949 to approximately 24 by 1961, fueled by the “Nifty Fifty” growth premium and a sustained earnings expansion. By the mid-1960s, the S&P 500 PE ratio peaked around 22–24, the structural high before the Great Inflation cycle.

1966–1982 — Inflation compression. Persistently high inflation and rising nominal rates compressed the PE from the low-twenties to single digits by 1979–1982. The August 1982 trough at PE near 7 marked the secular low of the post-war era and the launch point of the subsequent bull market.

1983–1999 — Real-rate decline and bull market expansion. Trailing PE expanded from approximately 7 in 1982 to approximately 33 at the December 1999 dot-com peak, with intermittent spikes above 40 in 1998–1999. The expansion tracked the multi-decade decline in real interest rates and the rising weight of higher-margin technology earnings in the S&P 500. The S&P 500 historical returns series captures the price-side companion to this regime.

2000–2009 — Bubble unwind and earnings-collapse spikes. The 2002 recession produced a PE spike near 47 (denominator effect from accounting write-downs); the 2009 reading reached above 120 as GAAP earnings briefly turned negative on aggregate. Both spikes were artifacts of the trailing methodology, not pure valuation extremes — a distortion the CAPE ratio filters out by smoothing earnings over a decade.

2010–2021 — Post-GFC low-rate regime. Trailing PE settled into a 17–25 range, supported by sustained low real rates and expanding corporate margins. The pandemic shock briefly pushed PE above 35 in 2020–2021 (earnings denominator effect again).

2022–2026 — Rate normalization. The Fed hiking cycle compressed the S&P 500 PE ratio back toward the low-twenties as real rates rose, with intermittent expansion during AI-driven earnings revisions. Cross-referencing the VIX and the Nasdaq Composite clarifies whether observed PE moves reflect price action or earnings revisions in higher-multiple segments.

Related Macroeconomic Datasets

Reading the S&P 500 PE ratio in isolation captures the cyclical valuation signal but misses its monetary and earnings drivers. The datasets below provide the cross-references needed for a complete macro-financial reading.

Macroeconomic Dataset Hub

This dataset is part of the Eco3min macro-financial data repository.

Explore the Eco3min Dataset Hub

Sources

• Robert Shiller, Yale University — ie_data.xls (Online Data, U.S. Stock Markets 1871–Present). Open academic data.
• Standard & Poor’s — Reported earnings, underlying series post-1957.
• Cowles Commission for Research in Economics — Pre-1926 earnings reconstruction.

Dataset Reference

Eco3min Research. (2026). S&P 500 Trailing Price-to-Earnings Ratio (1871–2026).<br> https://eco3min.fr/en/sp500-pe-ratio-dataset/