Chicago PMI explained

What the MNI Chicago Business Barometer measures

MNI emails a questionnaire each month to purchasing and supply executives at manufacturing firms in the Chicago metropolitan area and broader Great Lakes region. Respondents indicate whether activity in the current month is higher, the same, or lower than the prior month across standard PMI-style categories. The headline Business Barometer — the number markets call “Chicago PMI” — summarizes overall manufacturing conditions.

Published subindexes typically include:

• Production — current output flow; correlates with regional IP components
• New orders — forward demand; the best leading subindex in most months
• Order backlogs — unfilled work on hand; rising backlogs with strong new orders support future production
• Employment — hiring and headcount trends; moves slowly but confirms sustained shifts
• Supplier deliveries — vendor lead times; lengthening deliveries can signal demand pressure or logistics stress
• Inventories — customer and producer stock levels; compare with new orders for pipeline signals
• Prices paid — input cost pressure; leads goods-side PPI with a short lag

Unlike Federal Reserve regional surveys, Chicago PMI is a private MNI product (now part of Deutsche Börse Group). Methodology parallels ISM: diffusion indexes built from directional responses, not dollar-weighted order counts. The panel size is modest — on the order of 100–150 firms depending on response rates — which makes month-to-month volatility a feature, not a bug.

Diffusion index math and the 50 breakeven

Each Chicago PMI subindex follows the standard diffusion formula:

Index = % reporting higher + 0.5 × % reporting same

Scores range from 0 to 100. 50 is breakeven: equal shares of firms reporting improvement and deterioration, with unchanged responses split evenly. A reading of 55 means a net majority saw conditions improve — not that output grew 5%. A drop from 52 to 47 is a breadth flip among respondents, not a 5% production decline.

Because the Great Lakes panel is smaller than ISM's national sample, headline swings of 5–15 points in a single month are routine. Analysts who smooth with a three-month moving average or weight new orders over the headline reduce whipsaw substantially. Treating Chicago PMI like a hard-data growth rate is the most common interpretive error in month-end trading.

Regional scope: Great Lakes sector mix

The Chicago survey captures a manufacturing belt heavy on metals, machinery, transportation equipment, food processing, and chemicals. Illinois, Indiana, Michigan, and Wisconsin auto and steel supply chains weigh heavily on responses. The region has less semiconductor fabrication or Gulf Coast petrochemical capacity than Texas, and less aerospace final assembly than the Pacific Northwest.

That sector mix creates predictable divergences:

• Auto production schedules — Model-year changeovers and UAW negotiations can depress Chicago PMI while national ISM holds above 50.
• Steel and aluminum — Tariff headlines and mill maintenance outages move prices paid and production subindexes independently of services-heavy states.
• Weather — Great Lakes winter storms disrupt logistics; supplier delivery indexes spike without national demand collapse.
• Heavy machinery — Caterpillar-adjacent capital goods cycles lag consumer manufacturing and can turn down earlier or later than the national average.

Correlation with the national ISM Manufacturing PMI is positive — often 0.5–0.7 on headline levels — but far from lockstep. When Chicago PMI and Empire State or Philly Fed diverge sharply, the signal is often regional idiosyncrasy. When Chicago, Dallas Fed, and Kansas City Fed late-month surveys weaken together, national factory slowdown risk rises materially.

Calendar placement: the month-end manufacturing bookend

Chicago PMI's last-business-day timing makes it a calendar anchor:

Traders use Chicago PMI as a final sentiment read before the next ISM print confirms or contradicts the month. Bond and equity futures can move on large surprises, but month-end liquidity and window-dressing amplify volatility — moves often fade once ISM arrives. The productive use is updating a Bayesian prior for the next national PMI, not declaring a cycle turn on one Great Lakes headline at 9:45 a.m. on a Friday.

Reading subindexes: orders, backlogs, and prices

Experienced macro desks rarely trade the headline in isolation. A practical hierarchy for Chicago PMI:

1. New orders minus inventories — When new orders exceed 50 and inventories sit below 50, factories are meeting demand from stock; production tends to accelerate. The reverse pairing signals future cutbacks.
2. Production vs new orders — Production above new orders drains backlog; the opposite builds it. Cross-check with factory orders for national confirmation.
3. Order backlogs trend — Three consecutive months of falling backlogs with sub-50 new orders is a stronger slowdown signal than one sub-50 headline.
4. Prices paid — Input cost pressure feeds PPI goods discussions, not shelter-heavy CPI. A spike can reflect steel or energy in the Great Lakes without broad consumer inflation.
5. Supplier deliveries — Longer lead times during expansions are normal; during downturns, shortening deliveries can mean weak demand rather than improved logistics.
6. Employment — A single sub-50 print rarely precedes immediate layoffs; sustained weakness across multiple regional surveys does.

MNI occasionally publishes special commentary on tariffs, freight rates, or auto-sector disruptions. Treat one-off narrative boxes as qualitative color, not time-series comparable data unless the question repeats monthly.

Harbor Manufacturing month-end refactor

Harbor's legacy workflow emailed a “manufacturing contraction alert” to procurement whenever Chicago PMI printed below 50 — regardless of whether mid-month Empire State and Philly Fed had been strong, or whether durable goods orders were accelerating nationally. Steel buyers in Ohio and aluminum suppliers in Tennessee paused shipments on Great Lakes auto noise; the company carried excess safety stock through two quarters while national IP rose.

The refactor introduced four gates before procurement action:

• Smoothing — Alert only if the three-month average of Chicago new orders falls below 48.
• Cross-regional confirmation — Require at least one late-month Fed survey (Dallas or Kansas City) to agree on new-orders direction, or wait for the next ISM print.
• Hard-data check — No order pauses until prior-month IP, durable goods shipments, or capacity utilization corroborates the survey direction.
• Sector filter — Flag auto- and steel-weighted Chicago weakness separately from national capex and machinery lines; procurement rules differ by commodity.

Month-end procurement false stops fell from five per year to zero. Forecast error on steel input planning improved by 38 basis points versus the prior-year baseline. The macro desk still logs every Chicago PMI release for its month-end information value, but plant-level decisions now follow confirmed national signals — not a single Great Lakes diffusion print on the last Friday of the month.

Technique decision table: Chicago PMI vs alternatives

Common pitfalls

• Treating the headline like GDP growth — 47 is not a 3% contraction; it is net negative breadth among ~100+ Great Lakes firms.
• Overweighting month-end volatility — Last-Friday liquidity exaggerates futures moves; use three-month averages.
• Ignoring auto and steel sector bias — Great Lakes heavies can diverge from national ISM for quarters at a time.
• Expecting perfect ISM correlation — Chicago leads or lags ISM depending on the cycle phase; the link is noisy.
• Using prices paid as CPI forecast — It leads goods PPI, not services or shelter CPI.
• Skipping cross-regional confirmation — Compare with Dallas and Kansas City Fed surveys released the same week.
• Confusing private MNI with Fed data — Methodology is similar but panel and geography differ from Philly or Empire State.
• Procurement action on one print — Regional sentiment should not override national order books and hard data.

Production checklist

• Calendar Chicago PMI (last business day, 9:45 a.m. ET) with Dallas/Kansas City Fed and next ISM date.
• Archive full subindex table and MNI commentary, not just headline.
• Compute three-month moving averages for new orders and headline.
• Track new orders minus inventories and order backlog trend.
• Compare Chicago new orders direction with late-month Fed district surveys.
• Cross-check large surprises against prior-month IP and durable goods.
• Flag sustained sub-50 new orders across two or more regional surveys.
• Separate Great Lakes auto/steel color from national procurement rules.
• Include Chicago PMI in month-end manufacturing synthesis notes.
• Review false signals quarterly and adjust smoothing thresholds.

Key takeaways

• Chicago PMI is a Great Lakes diffusion index: 50 marks equal breadth of improvement and deterioration, not zero growth.
• Last-business-day timing makes it the final major manufacturing sentiment read each month, but the panel is volatile and sector-heavy.
• New orders, backlogs, and prices paid carry more signal than the headline alone.
• Confirm with late-month Fed surveys, next ISM print, and hard data before treating moves as national cycle turns.
• Harbor Manufacturing cut month-end procurement false stops to zero by smoothing, cross-regional confirmation, and sector-aware gates.

Related reading

• ISM Manufacturing PMI explained — national counterpart released on the first business day
• Empire State Manufacturing Index explained — mid-month NY Fed early read
• Industrial production explained — hard-data volume index for factory output
• Durable goods orders explained — Census orders and shipments confirmation