NEW YORK, September 6, 2026, 2:55 p.m. EDT — A transparent proxy puts the S&P 500 equity premium near 2.25%. The index closed Friday at 7,718.60. U.S. cash markets are shut Sunday.
The cushion is thin. It measures the extra earnings yield offered by stocks after a real Treasury return. Federal Reserve staff now see that trade-off near a historical extreme.
Owners of the SPDR S&P 500 ETF Trust NYSEARCA:SPY face two moving parts. Profits keep rising. Real rates can still erase much of their valuation benefit.
Current chart
A volatile month finished almost where it began
The one-month price change was roughly flat. Source: Yahoo Finance historical data.
The proxy starts with FactSet’s $361.38 calendar-2026 earnings estimate. Dividing that figure by Friday’s index level gives a 4.68% earnings yield. The latest 10-year real Treasury yield was 2.43%.
The spread
Stocks offer about 2.25 points above a real Treasury
S&P 500 earnings yield
4.68%
10-year real Treasury
2.43%
Equity-premium proxy
2.25%
Calculated from the index close and FactSet’s 2026 EPS estimate. Real-yield source: U.S. Treasury, Sept. 4. This is a transparent proxy, not the Fed’s proprietary series.
Subtracting the two leaves 2.25 percentage points. That is payment for uncertain profits, price swings and permanent loss. Investors once received far more protection.
The July Fed minutes gave the comparison unusual force. Staff said the premium was “at a level that has only been lower in recent history during the dot-com bubble.” They also judged asset-valuation pressure elevated.
This was a staff stability assessment. It was not a timing call. The same minutes credited high valuations to strong profits and enthusiasm for artificial intelligence.
Fresh earnings data support part of that optimism. FactSet analyst John Butters found that the 2026 estimate rose 6.1% during July and August. Seven of 11 sectors recorded increases.
The counterweight
Analysts raised profits instead of cutting them
2026 EPS revision
+6.1%
Q3 EPS revision
+1.2%
Sectors with 2026 increases
7 of 11
July 1 through Aug. 31. Source: John Butters, FactSet Earnings Insight.
Third-quarter estimates climbed 1.2%. They normally fall 1.7% over the comparable two months, based on FactSet’s five-year average. That is the bullish case.
Still, a richer safety margin demands a change somewhere. A 3% premium at today’s real yield implies an 18.4 multiple. With earnings fixed, that maps to roughly 6,655 on the index.
Scenario map
Rates or price can rebuild the cushion
Current proxy
2.25%
21.4× earnings · 2.43% real yield
If real yield drops 0.50 point
2.75%
Same price and earnings
If premium reaches 3%
About −13.8%
Index near 6,655 at unchanged earnings
Mechanical scenarios only. Markets can also adjust through faster profits, slower profits or several variables moving together.
The 13.8% gap is arithmetic, not a forecast. A half-point fall in the real yield would lift the same proxy to 2.75%. Faster earnings growth could widen it without lower prices.
Fed officials also described a harsher channel. An AI disappointment could reprice shares and weaken consumer spending. Some participants worried that debt-funded AI investment could spread stress through lenders.
A Sept. 2 Atlanta Fed paper tested that link. Economists Indrajit Mitra and David Rapach modeled hypothetical index falls of 25%, 35% and 50%. Each produced a substantive drop in real consumption.
Risks: The proxy uses one earnings horizon and one real yield. Revisions, inflation shocks and changing sector weights can alter it quickly. Historical extremes can persist for years.
Friday’s inflation report will update the rate side. The August consumer-price index arrives September 11 at 8:30 Eastern time. The Fed meets September 15–16.
Three officials preferred a July rate increase. That split makes real yields the fastest-moving part of this valuation equation. Earnings remain the stronger defense.
