An estimator who prices a structural steel package in March may not see the mill order placed until summer. When the subcontract price is fixed, the fabricator carries every change in steel prices between the bid and the buy. An escalation clause writes that risk into the contract as a formula, so the price moves by the same percentage as a named price index between two named months.
Most of these clauses use an index from the Bureau of Labor Statistics. A producer price index, or PPI, measures the average change in the prices that domestic producers receive for their output. BLS publishes a guide for contracting parties that tie prices to PPIs, and the steps below follow it. The guide also says BLS neither encourages nor discourages these clauses and does not help write contracts, so the wording of the clause belongs with your attorney.
What the steel indexes did in the past year
Over the 12 months to August 2026, the BLS index for steel mill products rose 23.4%. The index for hot rolled steel bars, plates and structural shapes rose 13.4%, and the index for goods that construction industries buy as inputs rose 8.9%. All three are not seasonally adjusted. The August values are first-published figures that BLS can still revise.
Steel mill prices rose 23.4% in the year to August 2026
BLS producer price indexes, rebased so that August 2025 = 100, not seasonally adjusted
| BLS index | Code | Index base | August 2025 | August 2026 | 12-month change |
|---|---|---|---|---|---|
| Steel mill products | WPU1017 | 1982=100 | 308.8 | 381.2 | 23.4% |
| Hot rolled steel bars, plates, and structural shapes | WPU101704 | June 1982=100 | 275.6 | 312.5 | 13.4% |
| Net inputs to construction industries, goods | WPUIP2300001 | June 1986=100 | 328.3 | 357.5 | 8.9% |
Each index has its own base period, so the chart divides each month by that index’s August 2025 value and multiplies by 100. The BLS guide uses the same step when a clause combines several indexes.
Pick the index
The guide asks the parties to cite each index by its full title and code, for example “the Producer Price Index for hot rolled steel bars, plates, and structural shapes, code WPU101704.” BLS has no single index called the Producer Price Index. It warns against citing the All Commodities index, which counts one price change several times as a material passes through stages of production.
A detailed index follows the material more closely. BLS says detailed indexes are also more likely to be discontinued or to miss a month when too few producers report, and it suggests citing commodity indexes at the 4- or 6-digit level or above. The clause should name a fallback for a missing month, such as the next higher-level index.
BLS also suggests indexing the inputs to a product. Its reasoning is that if every seller of a product tied its price to that product’s own index, the price could rise only after the index rose, and the index could rise only after the price did. For a fabricated steel package, the hot rolled bars, plates and shapes index tracks the fabricator’s main purchased material.
Write down the months and the data version
The base month is the month the price was set. Name it by month and year, such as March 2026, and leave the index value out of the contract. BLS revises and occasionally rebases its indexes, and a clause that names only the month always points to the current official figure.
Use the index that is not seasonally adjusted. Seasonal adjustment removes price swings that recur at the same time each year, and BLS says adjusted indexes generally do not belong in these clauses, because the clause is meant to pass along the price change that occurred.
Name the adjustment month the same way. BLS warns against wording such as “the index as of September 30,” which could mean the August index available on that date, the September index, or the October index.
Then choose the data version:
- PPI data usually come out between the 9th and the 16th of the following month.
- BLS revises each month’s index for up to 4 months after first publication.
- The version published 4 months after the first is final and does not change, apart from a correction or a rebasing.
First-published values let the parties settle within weeks of the adjustment month. Final values arrive about four months later and stay fixed after that. BLS asks the parties to agree on the version before the contract is signed.
A worked example
The figures below are an example with round numbers. A steel subcontractor holds a $2,000,000 subcontract priced in March 2026. The parties agree that $1,200,000, the steel material, moves with the hot rolled bars, plates and shapes index. The other $800,000 for shop and field labor stays fixed, although the BLS guide shows how a clause can move a labor share with the BLS Employment Cost Index.
The BLS method for adjusting part of a price divides the adjustable portion by 100. Here each 1% change in the index moves the price $12,000. The clause sets a 3% trigger, with no adjustment until the index has moved at least that far from the base month, and a ceiling of 10% of the adjustable portion, or $120,000. Adjustments run in both directions.
| Scenario | Base month index | Adjustment month index | Index change | Adjustment before cap | Adjustment paid |
|---|---|---|---|---|---|
| Index rises 12% | 300.0 | 336.0 | 12.0% | $144,000 | $120,000 |
| Index rises 2% | 300.0 | 306.0 | 2.0% | $24,000 | $0 |
| Index falls 5% | 300.0 | 285.0 | -5.0% | -$60,000 | -$60,000 |
In the first row the index rose 12.0%, which works out to $144,000, and the cap holds the payment to $120,000. In the second row the 2.0% rise is under the trigger, so the price stays at $2,000,000. In the third row the index fell 5.0%, and the owner receives a $60,000 credit.
The first row also shows why BLS strongly discourages clauses written in index points. The index rose 36.0 points. A clause paying $12,000 per point would pay $432,000, three times the percentage result, because one point is a third of a percent when the index stands at 300.
Where it fits with the other reports
Bill each adjustment as its own change order line. The change order rate post segments change orders by cause, and escalation can take its own cause code there.
Until an adjustment is approved, a steel price increase shows up as higher cost against an unchanged contract value, which the margin fade post and the work-in-progress schedule both track. The commercial furniture post covers the August steel and aluminum indexes in more detail.
How to start on your jobs
Pick one open subcontract or purchase order with a large steel share that was priced at least six months ago. Look up the hot rolled bars, plates and shapes index, code WPU101704, for the month it was priced and for the latest month, and compute the percent change.
Multiply that change by the material portion of the price. The result is the amount a clause would have moved on that job, and it gives you a starting point for the trigger and the cap on the next bid.