POLYMARKET RESEARCH / WORKED EXAMPLE
Polymarket Fed decision analysis
Will the Fed raise, hold or cut interest rates at its September 2026 meeting? Our first forecast puts a quarter-point hike at 77%, including a two-point adjustment from large-trade evidence. This full example shows the reasoning behind that estimate. SignalCast is independent and unaffiliated with Polymarket.
SIGNALCAST’S FIRST FORECAST
Our call: a quarter-point hike.
SIGNALCAST77%Our estimate
POLYMARKET78.5%At the research snapshot
THE DIFFERENCE−1.5percentage points
We favor a hike, with slightly less conviction than Polymarket at the snapshot. Inflation and the Fed’s signals support action. Uneven hiring and easing annual core inflation leave a real chance officials wait.
75% economic assessment+2 points large-trade adjustment=77% final call
| Rate decision | Polymarket at snapshot | SignalCast |
|---|---|---|
| 50+ bps increase | 0.65% | 1% |
| 25 bps increase | 78.5% | 77% |
| No change | 20.5% | 21% |
| 25 bps decrease | 0.35% | 0.8% |
| 50+ bps decrease | 0.05% | 0.2% |
Economic and trade evidence captured Sep 12, 10:08 AM ET. Forecast recorded Sep 12, 10:11 AM ET. Market quotes are preserved as supplied and may total slightly above 100%.
HOW WHALES AFFECT THIS CALL
Large trades reinforce the hike case.
In the quarter-point hike contract, we observed 24 trades of at least $10,000 across 15 wallets during the captured 24 hours. Hike-directed taker activity totaled $693,691, versus $105,064 opposing it.
86.8% hike-directed trade value13.2% opposing
That share remains 79.5% after removing the largest wallet and 72.9% after removing the two largest. The largest wallet accounts for 35.8% of observed value. The hold contract’s flow is mixed.
Our weighting: add 2 points to the hike and remove 2 from hold. This is a small editorial adjustment: trades can reflect hedging, and market prices already absorb some of this information. The cash threshold also favors higher-priced shares. The 86.8% trade share is a flow measure, not an 86.8% chance of a hike.
Counting method and limitations
Window: Sep 11, 10:08 AM ET to Sep 12, 10:08 AM ET. Source: Polymarket’s public trade feed, exact Fed contract. Duplicate records removed; cash value is shares × price. BUY Yes and SELL No count toward the hike; SELL Yes and BUY No oppose it. These are taker-side transactions, not net money entering the market or verified holdings. Wallets can trade both sides, and one person may control multiple wallets. The source page cap was not reached in this snapshot.
Method: first editorial estimate, supported by the research below. These weights have not been calibrated against a forecast history. Later revisions will be separate records.
BEHIND THE PROPOSITION
Dated research · Sep 12, 2026 · 9:39 AM ETInflation pushes toward a hike. The cost to jobs is the counterweight.
SignalCast analysis: The latest evidence strengthens the case for higher rates and weakens the immediate case for a cut. The real question is whether the Fed sees persistent inflation that requires a hike, or an energy shock it can wait out without damaging employment. A quarter-point move and a larger hike need different levels of evidence.
Meeting expectations does not mean meeting the target.
Headline CPI matched expectations, but monthly price growth accelerated. Annual headline CPI stayed flat and annual core CPI eased from 2.5% to 2.4%. So this release does not show every inflation measure moving farther away. The Fed’s 2% goal applies to PCE, which remains above target. Expectations report ↗ CPI data ↗ Fed target ↗
The energy shock can spread beyond the gas pump.
War-related supply and shipping disruption can raise fuel, freight and production costs. Businesses may pass those costs to customers, broadening inflation and strengthening the hike case. The Fed’s Beige Book already reports pressure from energy, transport and materials, alongside conflict uncertainty. Price-sensitive customers limit how much firms can pass through. Beige Book · Sep 2 ↗
There is an opposing channel: expensive energy also leaves households less to spend elsewhere and squeezes employers. If demand and hiring weaken enough, the same shock can support holding rates. This transmission analysis is conditional; oil does not mechanically determine the Fed’s decision.
Employment has not yet forced a rescue.
August’s job growth and steady unemployment give the Fed room to focus on prices. On August 28, Chair Warsh described labor conditions as stable and put the current emphasis on inflation; he did not treat better summer readings as proof that the underlying problem was solved. That is a policy signal, not a promised September vote. Jobs report ↗ Read his analysis ↗
The headline jobs gain also has a caution: restaurants and local-government education supplied 101,000 of the 162,000 jobs, and the education increase largely reversed an earlier decline. That leaves less evidence of broad hiring strength than the total alone suggests. Employment detail ↗
What would change the decision?
SignalCast interpretationPersistent oil disruption, broader price increases or rising inflation expectations, while employment holds up. A larger hike would need stronger evidence than a quarter-point increase.
Energy inflation appears temporary, underlying prices cool, or officials want more evidence about spending and the effects of existing rates.
A material deterioration in jobs or demand, alongside convincing inflation relief. The latest employment release alone does not establish that case.
Watch next: oil-supply and shipping developments, consumer spending, and the September 15–16 Fed decision and projections. July PCE predates the August CPI release; these are different measures and periods.
The first editorial forecast above is supported by this dated research. Sources are dated separately from live market prices. The Beige Book reflects business contacts, not a policy commitment. Research is manually reviewed during this preview.
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