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GDP growth in 2026? — 4.1 to 4.5

KXGDPYEAR-26-B4.3 · Economics · 2026-04-09

Agent

Market Price

+0.0%

Edge

72%

Confidence

Volume: 17,913

Spread: 0.6c

Days to resolution: 325

Markets in event: 14

Final Rationale

My independent estimate of ~3.3% and the market price of 3% are in near-perfect convergence, both reflecting the fundamental implausibility of 4.1-4.5% real GDP growth in 2026. The base rate for this specific range is ~8.5% since 1990 (concentrated in the late-1990s tech boom), and current conditions — 2025 ending with weak 1.4% Q4 growth, decelerating consumer spending, and significant tariff/trade war headwinds — push probability well below the base rate. I partially accept the Devil's Advocate critique on nominal vs. real GDP ambiguity (Challenge 1), but even nominal GDP growth landing precisely in 4.1-4.5% would require an unusual combination of factors given current inflation trends. I reject Challenge 5's suggestion that tail scenarios deserve meaningfully more weight — while 325 days is a long horizon, achieving 4.1-4.5% growth would require a massive positive shock without any plausible catalyst currently visible. The suspicious 96pp market drop likely reflects a contract repricing event, but the current 3% level is fundamentally sound.

Price vs. prediction

How the market moved after the agent's call. Solid blue line is the actual market price; dashed line is the agent's static forecast at $t{=}0$.

$n = 54$ follow-ups

1. Planner Opus · Fermi decomposition + tool plan

Tools chosen: article_search kalshi_data

Sub-questions (Fermi decomposition)

GDP growth in 2026? — 4.1 to 4.5 (w=1.00)

Planner reasoning

Fallback: general forecasting approach

2. Research Parallel tool calls · legacy v2

Tool	Status	Time	Items	Summary
article_search	OK	0.2s	-
kalshi_data	OK	0.2s	-

3. Evidence Synthesis Sonnet · 7 items · legacy v2

#	Strength	Credibility	Direction	Source	Claim	Priced In
1	STRONG	72	↓ DOWN	kalshi_data	Kalshi market prices 4.1–4.5% GDP growth in 2026 at only 3% probability, with a dramatic 30-day decline of 96 percentage points (from ~99% to 3%), suggesting a major revision in market expectations.	Yes
2	STRONG	92	↓ DOWN	article_search	U.S. GDP grew at only 2.2% for full-year 2025 and Q4 2025 came in at just 1.4% annualized rate, well below the 2.5% consensus estimate, dragged down by a 43-day government shutdown and weakening consumer spending.	Yes
3	WEAK	30	NEUTRAL	article_search	Trump Commerce Secretary Howard Lutnick predicted Q1 2026 growth exceeding 5% and full-year 2026 growth of 6%, far above the 4.1–4.5% range, though expert consensus was highly skeptical of these projections.	Yes
4	MODERATE	60	NEUTRAL	article_search	Analysts noted that despite the weak Q4 2025 GDP print, the economy 'remains on firm ground and is likely to accelerate in the coming months,' suggesting some rebound in 2026 is expected but not necessarily to 4.1–4.5%.	Yes
5	WEAK	55	↓ DOWN	article_search	China set its 2026 GDP growth target at 4.5–5%, its lowest in decades, reflecting global economic uncertainty — an indirect signal that global growth conditions remain uncertain heading into 2026.	Yes
6	STRONG	90	↓ DOWN	article_search	Full-year 2025 U.S. GDP growth was 2.2%, down from 2.8% in 2024. Historical U.S. GDP growth outside post-pandemic bounces rarely exceeds 3–3.5%, making 4.1–4.5% a historically unusual outcome.	Yes
7	MODERATE	65	↓ DOWN	article_search	Consumption was the biggest driver of 2025 GDP, not AI capex, and Q4 2025 saw consumer spending slowdown — raising questions about whether the primary growth engine can sustain an acceleration to 4%+ in 2026.	Yes

Information Gaps

No Q1 2026 GDP data or advance estimates available — unclear whether the anticipated rebound materialized.
No Federal Reserve interest rate path data for 2026 — rate cuts could provide upside surprise to growth.
No consensus economist forecasts for full-year 2026 GDP growth (e.g., from CBO, IMF, Fed, or major bank forecasters).
No data on tariff impacts or trade policy effects on 2026 growth trajectory.
No information on why the Kalshi market price declined so sharply over 30 days — was this driven by new economic data, revised forecasts, or a structural market change?
No clarity on whether the Kalshi market measures nominal or real GDP growth, or annualized quarterly vs. full-year.
No Q1 2026 consumer confidence or spending data to assess trajectory.

Key Uncertainties

The definition of '2026 GDP growth' in this context — whether it refers to full-year real GDP growth (annual average), Q4-over-Q4 growth, or nominal GDP — significantly affects the probability.
The dramatic 30-day Kalshi price collapse (99% → 3%) is unexplained and could reflect a market structure issue, a rules clarification, or genuine fundamental revision.
Whether post-shutdown economic rebound in 2026 could produce an unusually strong year, as some analysts hinted.
Tariff and trade war escalation risks that were emerging as of early 2026 could suppress growth well below historical trends.
Federal Reserve policy path — rate cuts could stimulate growth but timing and magnitude are uncertain.
U.S. fiscal policy trajectory (spending cuts, DOGE impacts) could further suppress government contribution to GDP.

Market Context

Price: 0.03 · 7d: -0.03 · 30d: -0.96
Volume: MODERATE · Depth: MEDIUM
Reliability: LOW-MEDIUM — The 96-percentage-point drop in 30 days is extreme and potentially reflects a structural market event (e.g., contract repricing, definition change) rather than pure fundamental reassessment. The current 3% price aligns with economic fundamentals suggesting 4.1–4.5% growth is unlikely, but the historical price path is suspicious and reduces reliability.

4. Independent Forecaster Opus · No market price · legacy v2 Did NOT see market price

Independent estimate: 3% (72% confidence)

base rate

72% conf

evidence driven

72% conf

contrarian

72% conf

Spread

1pp

Low disagreement

sq1: GDP growth in 2026? — 4.1 to 4.5

BASE RATE: U.S. real GDP growth has exceeded 4% in only a handful of years in the post-1990 era. Since 1990, the only years with 4%+ real GDP growth were 1997 (4.4%), 1998 (4.5%), 1999 (4.7%), 2000 (4.1%), and 2021 (5.9% - pandemic rebound). That's roughly 5 out of 35 years, or ~14% for exceeding 4%. But for the specific narrow band of 4.1-4.5%, it's even rarer — only 1997, 1998, and 2000 fall in that range, so roughly 3/35 = ~8.5% base rate. However, the years that achieved this were during the late-1990s tech boom with very favorable conditions. EVIDENCE UPDATES: - Full-year 2025 growth was only 2.2%, with Q4 2025 at 1.4% annualized. To reach 4.1-4.5% for full-year 2026 from a 2.2% baseline would require an extraordinary acceleration — roughly doubling the growth rate. This pushes DOWN significantly by ~3-4% from base rate. - Consumer spending, the primary growth engine, was already slowing in Q4 2025. This pushes DOWN by ~1%. - No post-pandemic rebound dynamic is in play (that was 2021). There's no structural reason for a massive bounce. Pushes DOWN by ~1%. - Tariff/trade war risks emerging in early 2026 are additional headwinds. Pushes DOWN by ~1%. - Government shutdown aftermath could produce some rebound, but unlikely enough to push growth to 4%+. Minimal upward push, ~0.5%. - Trump administration's optimistic 6% prediction is not credible per expert consensus. No meaningful upward adjustment. - Possible Fed rate cuts could help, but even aggressive rate cuts typically don't produce 4%+ growth within the same year. Small upward push ~0.5%. Starting from ~8.5% base rate, the strong evidence that 2025 ended weak at 2.2%, the absence of any pandemic-rebound-type catalyst, emerging trade war headwinds, and slowing consumer spending all push this down substantially. The probability of jumping from 2.2% to 4.1-4.5% without a major structural catalyst is very low. Final estimate: ~4%

Show full reasoning trace

base rate: U.S. real GDP growth has fallen in the 4.1-4.5% range in roughly 3 out of 35 years since 1990 (~8.5%), and those occurrences were during the exceptional late-1990s tech boom. Outside post-pandemic rebounds, 4%+ growth is very rare in the modern U.S. economy.

evidence updates: 2025 ended at 2.2% growth with Q4 at 1.4% — a very weak launching point. Consumer spending was decelerating. Emerging tariff/trade war risks add headwinds. No pandemic-rebound or tech-boom-level catalyst exists. These factors collectively push the probability well below the already-low base rate.

combination method: Single sub-question with 100% weight.

final: The combination of a low historical base rate for 4.1-4.5% growth, the weak 2025 economic trajectory, slowing consumer spending, and emerging trade policy headwinds makes this outcome quite unlikely. Estimated at 4%. Note: if this question refers to nominal GDP rather than real GDP, the probability would be meaningfully higher (nominal growth is typically 2-3pp above real), but the standard interpretation of 'GDP growth' is real GDP.

ensemble: {'ensemble_count': 3, 'perspectives': {'base_rate': {'p_yes': 0.04, 'confidence': 0.72}, 'evidence_driven': {'p_yes': 0.03, 'confidence': 0.72}, 'contrarian': {'p_yes': 0.03, 'confidence': 0.72}}, 'spread': 0.01, 'individual_p_yes': {'base_rate': 0.04, 'evidence_driven': 0.03, 'contrarian': 0.03}}

5. Devil's Advocate Sonnet · legacy v2 Market price revealed

Missing Info Reasoning Flaw

Challenges

The forecaster notes a critical information gap: 'No clarity on whether the Kalshi market measures nominal or real GDP growth, or annualized quarterly vs. full-year.' This is a fundamental ambiguity. If the question refers to nominal GDP growth, the probability would be meaningfully higher (the forecaster themselves acknowledges 2-3pp higher nominal vs real). If it refers to Q4-over-Q4 annualized growth rather than full-year average, a single strong quarter could produce a 4.1-4.5% reading. The forecaster defaults to 'real GDP, full-year' interpretation without confirming this, which could lead to underestimation.
The 30-day market drop of 96 percentage points is flagged as suspicious but not adequately explored. If the market previously priced this much higher and then crashed, it could indicate a contract definition change or repricing event rather than a fundamental reassessment. This matters because the current 3% market price might reflect a structural artifact rather than genuine probability assessment, making it less useful as a cross-check.
The forecaster lists 'No consensus economist forecasts for full-year 2026 GDP growth' as an information gap. With 325 days until resolution, mainstream forecasts from CBO, IMF, Fed, and major banks would be highly informative. The absence of this data should widen uncertainty somewhat rather than being treated as neutral.
The evidence update arithmetic is somewhat imprecise. Starting from 8.5% base rate, the forecaster applies multiple downward adjustments (3-4%, 1%, 1%, 1%) with small upward offsets (0.5%, 0.5%), which would mathematically yield roughly 8.5 - 3.5 - 1 - 1 - 1 + 0.5 + 0.5 = 3%, yet the stated result is 4%. This is a minor inconsistency but suggests the combination method is more intuitive than systematic.
With 325 days until resolution, there is substantial time for unexpected economic developments — fiscal stimulus, supply-side shocks, resolution of trade disputes, or other catalysts. The forecaster treats the current trajectory as largely deterministic, but over nearly a year, tail scenarios deserve slightly more weight. The confidence of 0.72 seems appropriate for this uncertainty, but the point estimate might be slightly too low given the long time horizon.

Market comparison: Forecaster: 3.3%, Market: 3.0%. Divergence of +0.3pp is negligible. Both assessments align on the fundamental implausibility of 4.1-4.5% GDP growth in 2026 given current economic conditions. The 96pp 30-day market drop is suspicious and warrants caution about using the market as a reliable signal, but the current price level is consistent with economic fundamentals.

6. Aggregator Opus · final calibrated forecast

3% (72% confidence)