The Senior Citizens League now projects the 2027 Social Security cost-of-living adjustment (COLA) at 3.5%, up from the 2.8% approved for 2026 and the 2.5% paid in 2025. The update, published on the morning of September 11, 2026, followed the Bureau of Labor Statistics August CPI release, which put the CPI-W component that drives COLA at 3.5% year over year. If TSCL’s estimate holds when SSA finalizes the number in October, retirees are looking at the biggest COLA in three years — and Washington is looking at another leg up in mandatory outlays at the exact moment the Treasury is trying to term-out its debt.
The number, and how TSCL got there
Social Security’s annual adjustment is not a discretionary vote — it is a formula. Each year, SSA takes the average of the Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W) for July, August, and September, and compares it to the average of the same three months a year earlier. Whatever percentage change comes out is the COLA for the following calendar year, effective with the December benefit paid in January.
Two of the three months are now on the board. With August CPI-W running at 3.5% YoY, TSCL’s model puts the 2027 COLA at 3.5% — a level that would translate into roughly $67.90 more per month for the average retired-worker benefit, taking the typical check from $1,940.08 to $2,007.98. The final number will move if the September CPI-W surprises in either direction, but a full percentage-point swing from here is unusual.
Recent COLA trajectory
The 2025 and 2026 COLAs both came in under 3%, near the long-run average for the series. A 3.5% print for 2027 would break the downtrend that followed the 8.7% cycle peak in 2023 and reflect the sticky-services and re-accelerating-energy dynamic captured in this morning’s headline CPI.
Why capital markets pay attention
Social Security is the single largest program in the federal budget. Every 100 basis points added to the COLA lifts mandatory outlays for the following year by a non-trivial amount and, because the trust fund’s cash surplus has been thinning, that increment must be financed. That is a Treasury supply story, not a retirement story.
Three linkages are worth watching:
- Treasury issuance: higher COLA payments raise the run rate of on-budget outlays that OASI must cover. When the trust fund’s own tax receipts fall short, the redemption of intragovernmental holdings turns into public borrowing — additional coupons and bills that hit the auction calendar.
- TIPS demand: retirees are the natural end-buyer of inflation-linked instruments, and a higher official inflation adjustment reinforces the case that CPI is not returning to a 2% neighborhood any time soon. That tends to support real yields at the front end and firm breakevens in the belly.
- Sticky-services feedback: COLA payments flow to consumers who spend heavily on shelter, healthcare, and services — the exact categories keeping core CPI at 2.4% YoY. The mechanism is not large in isolation, but it is procyclical to the same components the Fed is trying to cool.
What today’s CPI actually said
Headline CPI rose 0.4% in August on a seasonally adjusted basis and 3.4% over the last 12 months (unadjusted). Core CPI — the number the Fed watches for signal — was up 0.3% for the month and 2.4% year over year. Energy did the heavy lifting: the energy index rose 2.1% for the month, with gasoline alone up 3.9%. Shelter rose 0.3% MoM and 3.0% YoY, and food was up 0.1%.
The CPI-W subindex that feeds the COLA formula tracks the same basket with different expenditure weights, and this month it printed at 3.5% YoY per TSCL’s read of the release — enough to lift the July–August average into the range that supports a 3.5% projection.
Retiree impact at a glance
| Measure | Value |
|---|---|
| 2027 COLA (TSCL projection, Sep 11, 2026) | 3.5% |
| 2026 COLA (in effect) | 2.8% |
| 2025 COLA (prior year) | 2.5% |
| Average current monthly benefit | $1,940.08 |
| Projected 2027 average monthly benefit | $2,007.98 |
| Illustrative monthly dollar increase | +$67.90 |
How this frames the September FOMC
The FOMC meets September 15–16, 2026, with a Summary of Economic Projections. Coming into the print, the 10-year Treasury closed at 4.83% on September 9. A CPI-W reading that supports a 3.5% COLA is a reminder that the inflation the government pays retirees on is not decelerating to target — a fact that tends to keep the long end well-anchored to term premium arguments rather than to imminent-cut arguments.
For bond investors, the practical takeaway is that inflation-adjustment mechanisms across the federal budget — COLA, TIPS coupons, federal wage indexations — remain calibrated to a CPI that is running north of the Fed’s 2% goal. That mismatch keeps the Treasury’s inflation-linked obligations rising alongside its nominal ones.
What to watch next
- September CPI release (scheduled mid-October, per BLS) — the final input to the COLA formula. SSA typically announces the official number the same morning.
- Treasury Refunding Announcement — auction sizes for coupon issuance in the November–January window will indicate how the Treasury is financing rising mandatory outlays.
- Sept 16 FOMC SEP — updated dots and inflation forecasts will show whether policymakers see August’s core surprise as a bump or an inflection.
Sources
- TSCL press release — 2027 COLA projection at 3.5%
- BLS — Consumer Price Index Summary (August 2026)
- Federal Reserve — FOMC meeting calendar
- FRED — 10-Year Treasury Constant Maturity Rate
Disclosure: This article is for informational purposes only and is not investment advice.