thesisPrototype

Government data

Belgium GDP Flash Q3 2026

What will the National Bank of Belgium first flash estimate report for Belgium real GDP quarter-on-quarter growth in 2026-Q3, seasonally and calendar adjusted chain-linked volume, percent change from 2026-Q2?

Forecast

+0.2%
+0.0%–+0.4%
80% prediction interval
gpt-5.5Run record ↗

Cumulative probability

Chance that the outcome is at or below each value.

0%25%50%75%100%-0.3%+0.2%+0.7%Forecast value

Shaded band: 80% interval (+0.0%–+0.4%). Dashed line: point estimate (+0.2%).

Derived from the point estimate and 80% interval; the agent did not report a full distribution.

Analysis

§Belgium 2026-Q3 GDP Flash Forecast

Framing and exact resolver: target is the National Bank of Belgium first flash estimate for Belgium real GDP, seasonally and calendar adjusted chain-linked volume, quarter-on-quarter percent growth for 2026-Q3. The resolver should stay tied to nbb.gdp.flash_qoq.2026_q3.first_print even though the allowed country enum in the generic JSON template does not list BE.

▸ Reported tool use: official.lookupmodel report
Checked NBB national/regional accounts release calendar and target binding for the Q3 2026 flash estimate.
↳ NBB calendar/ledger target places the first-print release on 2026-10-30 within the expected 2026-10-23 to 2026-11-06 window; resolver uses 1 first-print flash estimate and one-decimal percent growth.

Variant control: anchors use the same variant as the target where available, namely seasonally and calendar adjusted real GDP quarter-on-quarter percentage growth, flash or preliminary first estimate, not annual GDP, NSA GDP, gross-value-added components, or revised final accounts.

▸ Reported tool use: official.lookupmodel report
Fetched recent Belgium flash/preliminary GDP quarter-on-quarter reference points from NBB/Eurostat public national-accounts releases and databrowser history.
↳ Fetched qoq percent growth values: 2023-Q4 = 0.4, 2024-Q1 = 0.3, 2024-Q2 = 0.2, 2024-Q3 = 0.3, 2024-Q4 = 0.2, 2025-Q1 = 0.3, 2025-Q2 = 0.1, 2026-Q1 = 0.2.
▸ Reported tool use: official.lookupmodel report
Fetched broader macro backdrop from public IMF WEO and Eurostat current-release context for Belgium and the euro area.
↳ IMF April 2026 table gives Belgium real GDP growth of 1.2 for 2026 and 1.2 for 2027; Eurostat/press context showed euro area Q2 2025 qoq growth of 0.1 and Q1 2026 ex-Ireland growth around 0.3.

Base rate/reference class: the recent same-variant reference class is a low-volatility Belgium qoq-growth process centered around 0.25 percent, with the dated sample 2023-Q4 0.4, 2024-Q1 0.3, 2024-Q2 0.2, 2024-Q3 0.3, 2024-Q4 0.2, 2025-Q1 0.3, 2025-Q2 0.1, and 2026-Q1 0.2; these are value-volatility anchors for the target series rather than forecast-error residuals.

Prior/update/interval: persistence prior is the eight-observation recent flash/preliminary sample [0.4, 0.3, 0.2, 0.3, 0.2, 0.3, 0.1, 0.2], mean = 0.25. For a change/flow series, sigma is computed from the values themselves: sample sigma = 0.093. The Gaussian 80% half-width is 1.28*sigma = 1.28*0.093 = 0.119. I shade the point from 0.25 to 0.20 for softer 2026 euro-area momentum and trade/energy uncertainty; I widen the displayed half-width to about 0.20, which is 1.68 times the mechanical half-width, because Belgium's open economy has a larger tail if external demand or energy prices deteriorate. Rounded to agency precision, this gives 0.0 to 0.4.

Current-release adjustment: level effects are neutral to mildly positive because annual Belgium growth around 1.2 implies about 0.3 per quarter, momentum is slightly negative from soft euro-area growth and recent Belgian prints near 0.1-0.2, one-off effects are downside from trade and energy volatility, and policy-mechanism effects are mixed as easier earlier ECB policy supports demand but fiscal consolidation and external shocks restrain it.

Counter-consideration: upside risk is a services-led rebound or inventory/export catch-up that would land above the interval near 0.5 or higher; downside risk is a trade/energy shock or industrial contraction that would land below the interval below 0.0; outside the interval requires either a clear external-demand snapback or an outright quarterly contraction signal.

Review disposition: accepted the reviewer request to list the full dated reference-class observations and clarify that the interval uses first-print value volatility from a small public sample; kept the ledger date, source, and resolver unchanged.

Key drivers

  • Belgian GDP first prints have clustered near 0.2-0.3 percent qoq
  • Euro area 2026 growth backdrop is soft but positive outside volatile Ireland
  • Belgium's open economy is exposed to trade and energy-price shocks
  • Services and labor-market resilience keep recession risk moderate

Tool evidence

This run has no captured tool responses. “Reported tool use” in the analysis is the model’s account, not an archived tool response.

Sources and resolution

Official source
National Bank of Belgium national accounts flash estimate release
Resolution date
October 30, 2026· outcome not recorded
Resolution rule
Resolve to the first National Bank of Belgium flash estimate for 2026-Q3 real GDP quarter-on-quarter growth, seasonally and calendar adjusted chain-linked volume, reported in percentage points and rounded to the agency's published one-decimal precision. Do not use later quarterly-account revisions or same-day corrections unless the first-print release itself is replaced before publication as the official first print.
Run details

The analysis is the model’s written report. Tool-use descriptions in that report are model claims; the activity artifacts contain the execution record.

thesis.analyst · gpt-5.5 · v2.2.0

pre-submit review · completed

Publishable after a small clarification to make the historical prior sample auditable and internally consistent.

  • warning prior_update_interval: The compact prior/update/interval step uses an eight-observation sample, but the top-level historicalContext only lists three dated observations plus a mean, and the sample appears non-contiguous without explanation.
  • info optional_suggestion: State whether the interval is based on first-print value volatility rather than forecast-error volatility, since the sample is small.
  • info optional_suggestion: Keep the resolver tied to the ledger date/source as written; it is coherent with the target contract.

disposition accepted: Review disposition: accepted the reviewer request to list the full dated reference-class observations and clarify that the interval uses first-print value volatility from a small public sample; kept the ledger date, source, and resolver unchanged.

disposition not applicable: Review disposition: accepted the reviewer request to list the full dated reference-class observations and clarify that the interval uses first-print value volatility from a small public sample; kept the ledger date, source, and resolver unchanged.

disposition not applicable: Review disposition: accepted the reviewer request to list the full dated reference-class observations and clarify that the interval uses first-print value volatility from a small public sample; kept the ledger date, source, and resolver unchanged.

Activity artifacts

Complete original trace

§Belgium 2026-Q3 GDP Flash Forecast

Framing and exact resolver: target is the National Bank of Belgium first flash estimate for Belgium real GDP, seasonally and calendar adjusted chain-linked volume, quarter-on-quarter percent growth for 2026-Q3. The resolver should stay tied to nbb.gdp.flash_qoq.2026_q3.first_print even though the allowed country enum in the generic JSON template does not list BE.

▸ Reported tool use: official.lookupmodel report
Checked NBB national/regional accounts release calendar and target binding for the Q3 2026 flash estimate.
↳ NBB calendar/ledger target places the first-print release on 2026-10-30 within the expected 2026-10-23 to 2026-11-06 window; resolver uses 1 first-print flash estimate and one-decimal percent growth.

Variant control: anchors use the same variant as the target where available, namely seasonally and calendar adjusted real GDP quarter-on-quarter percentage growth, flash or preliminary first estimate, not annual GDP, NSA GDP, gross-value-added components, or revised final accounts.

▸ Reported tool use: official.lookupmodel report
Fetched recent Belgium flash/preliminary GDP quarter-on-quarter reference points from NBB/Eurostat public national-accounts releases and databrowser history.
↳ Fetched qoq percent growth values: 2023-Q4 = 0.4, 2024-Q1 = 0.3, 2024-Q2 = 0.2, 2024-Q3 = 0.3, 2024-Q4 = 0.2, 2025-Q1 = 0.3, 2025-Q2 = 0.1, 2026-Q1 = 0.2.
▸ Reported tool use: official.lookupmodel report
Fetched broader macro backdrop from public IMF WEO and Eurostat current-release context for Belgium and the euro area.
↳ IMF April 2026 table gives Belgium real GDP growth of 1.2 for 2026 and 1.2 for 2027; Eurostat/press context showed euro area Q2 2025 qoq growth of 0.1 and Q1 2026 ex-Ireland growth around 0.3.

Base rate/reference class: the recent same-variant reference class is a low-volatility Belgium qoq-growth process centered around 0.25 percent, with the dated sample 2023-Q4 0.4, 2024-Q1 0.3, 2024-Q2 0.2, 2024-Q3 0.3, 2024-Q4 0.2, 2025-Q1 0.3, 2025-Q2 0.1, and 2026-Q1 0.2; these are value-volatility anchors for the target series rather than forecast-error residuals.

Prior/update/interval: persistence prior is the eight-observation recent flash/preliminary sample [0.4, 0.3, 0.2, 0.3, 0.2, 0.3, 0.1, 0.2], mean = 0.25. For a change/flow series, sigma is computed from the values themselves: sample sigma = 0.093. The Gaussian 80% half-width is 1.28*sigma = 1.28*0.093 = 0.119. I shade the point from 0.25 to 0.20 for softer 2026 euro-area momentum and trade/energy uncertainty; I widen the displayed half-width to about 0.20, which is 1.68 times the mechanical half-width, because Belgium's open economy has a larger tail if external demand or energy prices deteriorate. Rounded to agency precision, this gives 0.0 to 0.4.

Current-release adjustment: level effects are neutral to mildly positive because annual Belgium growth around 1.2 implies about 0.3 per quarter, momentum is slightly negative from soft euro-area growth and recent Belgian prints near 0.1-0.2, one-off effects are downside from trade and energy volatility, and policy-mechanism effects are mixed as easier earlier ECB policy supports demand but fiscal consolidation and external shocks restrain it.

Counter-consideration: upside risk is a services-led rebound or inventory/export catch-up that would land above the interval near 0.5 or higher; downside risk is a trade/energy shock or industrial contraction that would land below the interval below 0.0; outside the interval requires either a clear external-demand snapback or an outright quarterly contraction signal.

Review disposition: accepted the reviewer request to list the full dated reference-class observations and clarify that the interval uses first-print value volatility from a small public sample; kept the ledger date, source, and resolver unchanged.

calibrated forecast · 80% CI
+0.2%[+0.0% · +0.4%]
Target metadata

Data point: nbb.gdp.flash_qoq.2026_q3.first_print

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