Plant Price Indices 2026: Key Points for Reviewing Public Contracts

Key data

Contractor companies in the public sector with price revision clauses in their contracts have had, since April 14, 2026, a key technical instrument to calculate and claim economic adjustments: Order HAC/351/2026 publishes the complete series of plant price indices from December 2011 to the first quarter of 2025.

This publication is not a minor bureaucratic formality. Without these indices, neither contractors nor administrations can correctly calculate the price revisions agreed in the contract. Its absence has been, in many cases, the origin of disputes and claims that can now be resolved with complete official data.

What does this regulation establish?

Order HAC/351/2026 publishes the plant price indices corresponding to the complete series from December 2011 to the first quarter of 2025. These indices are technical instruments of mandatory reference for applying price revision clauses in contracts concluded with Public Administrations.

The mechanism works as follows: when a public contract includes a price revision clause referenced to plant indices, the contract amount can be adjusted if the cost of those inputs varies significantly. To calculate that adjustment, it is essential to have the official indices for the corresponding period.

The publication of the complete historical series has special relevance: it covers a period of more than thirteen years, which makes it possible to apply price revisions both in contracts currently being executed and in contracts already completed on which there are pending claims or disputes.

Its publication is mandatory by law so that contractors and administrations can correctly calculate the agreed revisions. Without these indices officially published, the calculation lacks valid legal basis.

Economic and operational impact

The economic impact of this regulation can be very significant for companies with public contracts of considerable volume. Price revisions in contracts for works, supplies or services can represent significant adjustments to the original contract amount, especially in periods with high cost variation such as those recorded between 2021 and 2023.

From an operational perspective, the availability of the complete series has two direct consequences:

• Contracts in progress: It allows correct application of pending price revisions to be calculated or settled, avoiding disputes with the Administration.
• Contracts already executed: It opens the door to claim price revisions that were not applied at the time due to lack of official indices, or to resolve already initiated disputes with complete and official technical data.

Companies that do not correctly apply these revisions—or that do not claim them when they are entitled to—may be leaving money on the table or, conversely, exposing themselves to claims from the Administration for overpayment.

Who does it affect?

This regulation directly affects:

• Construction and engineering companies with public works contracts that include price revision clauses referenced to plant indices.
• Service companies with service contracts with the Administration that contain such clauses.
• Supplier companies of goods to public bodies under contracts with price revision.
• Finance and contracting departments of any company with a portfolio of active or recently completed public contracts.
• Legal advisors and consultants who manage claims or disputes over price revisions in public contracts.
• Public Administrations as contracting parties, obliged to correctly apply the indices in settlements.

Practical example

Suppose a construction company that executed a public works contract between 2019 and 2022, with a price revision clause referenced to plant indices. During execution, the costs of certain inputs increased considerably, but the revision could not be calculated correctly because the official indices for the period were not completely available.

With the publication of Order HAC/351/2026, that company now has the official indices for the entire period between December 2011 and the first quarter of 2025, including the years 2019 to 2022. This allows it to:

• Calculate the exact amount of the price revision that corresponds to it.
• Submit a well-founded claim to the contracting Administration.
• Provide official technical documentation in case of litigation or arbitration.

If the contract had an amount of several million euros and the variation of the indices was significant in that period, the resulting price revision can represent an economically relevant amount for the company.

What should companies do now?

1. Review the portfolio of active and recent public contracts: Identify which contracts include price revision clauses referenced to plant indices and in which periods they were executed.
2. Verify if there are pending price revisions to calculate or settle: With the complete series now available (December 2011 — first quarter of 2025), check if there are unapplied adjustments that correspond to you.
3. Evaluate claims on already completed contracts: If you have pending disputes or claims over price revisions, the publication of this complete historical series may be the technical data that was missing to resolve them.
4. Coordinate with the legal department or external advisor: Ensure that whoever manages the claims or settlements is aware of the existence of this series and uses it correctly in the calculations.
5. Act quickly on claims with ongoing deadlines: If you have open administrative or judicial proceedings on price revisions, incorporate these indices as technical evidence before the procedural deadlines expire.