Tools chosen: polymarket_direct polymarket_related kalshi_related claude_news claude_news gdelt_news fred wikipedia code_execution

Sub-questions (Fermi decomposition)

Planner reasoning

This is a Polymarket question on whether the BoE holds Bank Rate at its 17 Sep 2026 MPC meeting. Key drivers are current Bank Rate level, UK inflation/labour data, market-implied path (SONIA/OIS), and the BoE's recent pattern of cutting only at 'MPR' meetings (Feb/May/Aug/Nov) — September is a non-MPR meeting, which historically raises the base rate of no change. I'll anchor on the Polymarket price, cross-check Kalshi, and gather UK macro and BoE commentary.

# Current state The Bank Rate has held steady at 3.75% through five consecutive MPC meetings in 2026 (Feb, Mar, Apr, Jun, Jul), with hawkish dissent growing (0→1→2→3 members voting to hike) amid a Middle East-driven energy/inflation shock. The next (September 2026) meeting is a non-MPR meeting, historically the most hold-biased type; OIS pricing as of mid-Aug 2026 implies ~75% probability of a hold. # Timeline of key events - 2026-02-04 (confirmed): MPC votes 5–4 to hold at 3.75%; 4 dissents for a 25bp cut. [bankofengland.co.uk] - 2026-03-18 (confirmed): MPC votes unanimously to hold at 3.75%. [bankofengland.co.uk] - 2026-04-29 (confirmed): MPC votes 8–1 to hold; 1 dissent for a 25bp hike. [bankofengland.co.uk] - 2026-06-17 (confirmed): MPC votes 7–2 to hold; 2 dissents for a hike. CPI 2.6% in June. [bankofengland.co.uk] - 2026-07-29/30 (confirmed): MPC votes 6–3 to hold at 3.75%; 3 dissents (Pill, Greene, Mann) for a hike to 4%, citing energy-driven inflation risk. Central projection: CPI peaking ~3.2% in Q4 2026. [bankofengland.co.uk, lbc.co.uk] - 2026-08-12 (reported): OIS/SONIA pricing implies ~75% probability of hold at Sept meeting; market-implied move only +6bp. [bluegamma.io] - 2026-09-17 (scheduled): Next MPC decision, resolution event for this market. # Event Will the Bank of England leave Bank Rate unchanged at its September 17, 2026 MPC meeting (relative to the pre-meeting level)? # Outcomes to forecast - Yes — No change in Bank Rate - No — Any change (hike or cut) in Bank Rate # Kalshi market anchor No direct Kalshi price was returned by kalshi_direct/kalshi_related tools for this specific ticker (only tangential Fed-related Kalshi markets surfaced, e.g., KXNEXTATLFED at 8%, unrelated). The best available cross-venue anchor is **Polymarket at 89.5% for "No change"** (7d: -1pt; 30d: +38pts; range 51.5%–94.5% over 51 days), reflecting a market that has swung firmly toward "hold" as the year progressed. # Sub-question answers 1. **Polymarket price for 'No change'** — 89.5% currently, up sharply from a 30-day low near 51.5%, essentially flat over the last week (-1pt). [polymarket_direct] 2. **Bank Rate level & 2026 meeting history** — Held at 3.75% at every 2026 meeting to date (Feb, Mar, Apr, Jun, Jul); no changes made all year. [bankofengland.co.uk] 3. **OIS/SONIA and analyst forecasts** — OIS as of Aug 12, 2026 implies ~75% probability of hold, market-implied move only +6bp; BofA, ING, Deutsche Bank, Oxford Economics all expect a hold through year-end. [bluegamma.io, hoa.org.uk] 4. **Base rate of 'no change' at non-MPR meetings** — Historically ~63% (full 2021-2025 sample); in the recent post-hiking-cycle regime (Sep 2023–Sep 2025), 100% (9/9) of non-MPR meetings resulted in holds. [code_execution analysis] 5. **Latest CPI/wages/unemployment** — CPI 2.6% (June 2026, above 2% target), projected to peak ~3.2% in Q4 2026 due to energy shock; core inflation 2.6% (down from 3.1% in Jan); services inflation 3.6% (down from 4.4% in Jan); unemployment 4.9% (3m to May), wage growth at 6-year low. Mixed: inflation trending up short-term (energy), but labour market and wages trending dovish. [commonslibrary.parliament.uk, moneyweek.com] 6. **MPC guidance/dissent direction** — No explicit "gradual and careful" cut language found in current research; instead dissent has shifted hawkish (toward hikes, not cuts) each meeting in 2026, from 0 to 3 members favoring a 25bp increase by July. This suggests hike risk, not cut risk, is the live tail risk for September. [bankofengland.co.uk] 7. **Other venues vs Polymarket** — No independent Kalshi-specific BoE September market or Polymarket "related" market found (0 matches on keyword scans); Polymarket's 89.5% stands largely uncorroborated by a second venue in this research set. # Key facts (high-confidence, factual) 1. [bankofengland.co.uk] Bank Rate unchanged at 3.75% since at least Feb 2026 through July 2026 (5 consecutive holds). 2. [bankofengland.co.uk] July 2026 vote was 6–3, with all 3 dissents favoring a hike (not a cut). 3. [bluegamma.io] OIS pricing (Aug 12, 2026) ~75% hold probability for Sept meeting. 4. [commonslibrary.parliament.uk] CPI 2.6% (June 2026), BoE projects peak ~3.2% in Q4 2026 amid Middle East energy shock. 5. [polymarket_direct] Polymarket "No change" price 89.5%, up from a 30-day low of 51.5%. # Cross-market signals - Kalshi related: no direct or closely matching market found; unrelated Fed-focused Kalshi contracts surfaced only. - Polymarket: 89.5% "No change," rising trend over 30 days, modest recent pullback (-1pt/7d). - Sportsbook implied: N/A (not applicable to this event type). # Analyst opinions and speculation - BofA, ING, Deutsche Bank, Oxford Economics: hold expected through year-end/into 2027 (hoa.org.uk). - NIESR (pre-energy-shock, likely stale): had expected two cuts to 3.25% by year-end — largely superseded by the energy shock narrative. - Growing hawkish minority (3 of 9 MPC members by July) raises tail risk of a hike surprise, not a cut. # Directional lean per outcome - **Yes (No change)**: Strongly supported — 5 straight 2026 holds, 75% OIS-implied hold probability, ~63-100% historical non-MPR hold base rates, Polymarket at 89.5%, multiple bank forecasts aligned on hold. - **No (Change)**: Weak but non-trivial — driven by hawkish dissent trend (3/9 favoring hike) and elevated energy-driven inflation (peak 3.2% projected Q4); a hike is more plausible than a cut given labor market/wage softness is not yet strong enough to flip the majority toward cutting. # Gaps / unknowns - No live Kalshi YES price could be retrieved for this specific ticker; Polymarket used as best proxy. - No August 2026 MPC meeting minutes/vote were provided (Aug is MPR; not confirmed here) — data gap between July and September. - No confirmed direct OIS/SONIA reading post-Aug 12, 2026, closer to the Sept 17 decision. # Calibration anchors - Polymarket "No change" price: 89.5% (best available cross-market anchor; no Kalshi-direct price obtained). - Historical recent-regime non-MPR hold rate: 100% (9/9, small sample) vs. full-sample non-MPR hold rate: ~63%. - OIS-implied hold probability (Aug 12, 2026): ~75%.

1. Both forecasts land between the OIS (75%) and Polymarket (89.5%) anchors but neither explains why they weight Polymarket—a thin, likely low-liquidity, non-BoE-specific market that swung from 51.5% to 89.5% in 30 days—more heavily than the more directly relevant OIS/SONIA pricing; this recency-driven swing could reflect a temporary squeeze or low-information traders rather than genuine informational content, and averaging toward it without justification risks anchoring bias. 2. Neither forecaster addresses the critical data gap explicitly flagged in the brief: no August 2026 MPR meeting data is provided, meaning between July (6-3 hold, 3 hawkish dissents) and September there's an entire unconfirmed MPC decision that could materially shift the vote count (e.g., if the hawkish bloc grew to 4-5 members in August, that would sharply raise hike probability for September beyond what's priced in the Aug 12 OIS snapshot). 3. Both forecasts almost entirely reduce "No" to hike risk, but this conflates two very different resolution mechanisms (hike vs. cut) into one number without decomposing them—if the outcome question is symmetric ("any change"), a proper forecast should explicitly estimate P(hike) and P(cut) separately even if cut risk is currently near-zero, since the brief notes wage/unemployment softness as a latent dovish factor that could reassert itself. 4. Neither model heavily engages with the historical base-rate discrepancy noted in the brief (100% hold in recent 9/9 non-MPR sample vs. only ~63% in the full 2021-2025 sample)—both implicitly favor the small, recent-regime sample without acknowledging the sample-size fragility (9 observations) or that the full-sample base rate is a full 37 points lower, which should arguably pull the estimate down from ~88-89% toward something more measured. 5. Both forecasts settle on very similar point estimates (0.88 and 0.84) despite claiming independent reasoning, and neither stress-tests a scenario where the Middle East energy shock intensifies unexpectedly before September 17 (a genuine tail risk given CPI is already projected to peak at 3.2% in Q4)—this could push the hawkish dissent from 3/9 to a majority swing far more abruptly than either forecast's ~12-16% "No" allocation implies. 6. Neither critique addresses that the Kalshi YES price itself was never actually retrieved ("No direct Kalshi price was returned"), yet both forecasters proceed to calibrate as if Polymarket is a suitable one-to-one substitute for the Kalshi contract's specific resolution criteria and settlement mechanics, which may differ (e.g., different meeting-outcome definitions or timing nuances) — this substitution risk is understated in both rationales.

86% (67% confidence)

Yes: 86% No: 14%

Five consecutive 2026 holds at 3.75%, a non-MPR September meeting (100% holds in the recent 9/9 post-hiking regime), and consensus bank forecasts for no change all point strongly to Yes. Market anchors bracket the estimate: OIS on Aug 12 implied ~75% hold (a month stale, and typically a lower bound since it prices expected move magnitude), while Polymarket sits at 89.5% but is thin and recently volatile; I split closer to Polymarket while haircutting for its low-liquidity swing and the substitution risk versus the actual Kalshi contract. The residual 14% is almost entirely hike risk (Pill/Greene/Mann dissenting for 4% in July with CPI projected to peak ~3.2%), with cut risk near-negligible given the hawkish drift, though softening wages/unemployment keep a small dovish tail alive. The unresolved August MPR outcome is the main uncertainty, but it cuts both ways — a hike in August would likely make September a hold, so it modestly supports rather than undermines Yes."}

Total pipeline time: 289.4s