Price Adjustment Clauses in German Supply Contracts

What is a price adjustment clause and how does it work?

A price adjustment clause is a form of value-protection clause (Wertsicherungsklausel). The supplier reserves the right to adjust the price when its own costs change, and does so not at its free discretion but tied to an objective benchmark. As a rule this benchmark is an official index, for example the producer price index for industrial products (Erzeugerpreisindex gewerblicher Produkte) published by the Federal Statistical Office for a raw material, or a labour cost index for the labour share.

Technically, the clause works with a weighting. The price is split into a fixed share and cost-dependent shares. Only the cost-dependent shares move with the respective index. The common base formula is:

P₁ = P₀ × (a + b × M₁/M₀ + c × L₁/L₀)

Here P₀ is the initial price, P₁ the adjusted price, a the fixed share, b the material share and c the labour share (a + b + c = 1). M₀ and M₁ denote the material index at the base date and at the settlement date, and L₀ and L₁ correspondingly the labour index. If an index falls or rises, only the associated share shifts. The fixed share stays constant. This split ensures that the adjustment reflects the actual cost structure and is not misused as a hidden profit lever.

Automatic or optional price adjustment clause: where is the difference?

Practice distinguishes two types. With the automatic price adjustment clause (echte Preisgleitklausel) the price change follows automatically from the index movement. If the reference value changes, the price changes in the same direction and to the same extent, without any party having to act. With the optional price adjustment clause (unechte Preisgleitklausel) the index movement merely triggers an adjustment right. The price only changes once a party demands the adjustment, often tied to a threshold such as an index change of more than three or five percent.

The difference is more than a formality. In Section 1(1) the PrKG in principle prohibits clauses that automatically tie a monetary debt to the value of non-comparable goods. An automatically operating clause therefore needs a statutory exception in order to stand. For supply contracts that exception is the cost-element clause under Section 1(2) no. 3 PrKG: the price may be linked automatically to a cost factor if that factor directly influences the supplier's own costs. Anyone who does not meet this exception cleanly is on the safer side with the optional variant, because mere adjustment rights without automation do not fall under the prohibition.

When is a price adjustment clause permissible in B2B?

Permissibility has two review levels that are often confused. The first is the PrKG, the second is the standard-terms review (AGB-Kontrolle) under Sections 305 et seq. BGB. Both must be passed.

At the PrKG level, the cost-element clause rescues the automatic adjustment, provided the index used actually reflects a cost component of the supplier. A steel price index for a steel processor, an energy index for an energy-intensive producer, a labour index for a labour-intensive service provider. A reference to unrelated variables, such as the gold price for a plastics supplier, breaks the cost-element clause.

The reference value must also be sufficiently specific so that both sides can follow the adjustment. In pre-formulated clauses this specificity requirement follows above all from the transparency requirement of Section 307(1) sentence 2 BGB; the narrower specificity requirements of Section 2 PrKG directly concern only the indexation clauses of Sections 3 et seq. PrKG, not the cost-element clause of Section 1(2) no. 3, which is exempt from the prohibition anyway.

At the standard-terms level, the fairness review under Section 307 BGB applies even between businesses. Although the clause prohibitions of Sections 308, 309 BGB do not apply directly in B2B (Section 310(1) BGB), they have indicative effect. In settled case law the Federal Court of Justice (Bundesgerichtshof, BGH) requires that a price adjustment clause allow only the compensation of increased costs and not serve to increase profit.

Where comprehensible benchmarks are missing, the clause is entirely unenforceable under Section 307 BGB. The position is different for a genuine individually negotiated agreement (Individualvereinbarung) settled between the parties: it is not subject to standard-terms fairness review and allows considerably more latitude.

Standard terms or individually negotiated agreement: why the classification decides

Whether a clause counts as standard business terms (Allgemeine Geschäftsbedingungen, AGB) or as an individually negotiated agreement shifts the review standard considerably. Standard terms are pre-formulated conditions intended for a multitude of contracts and imposed unilaterally (Section 305(1) BGB). As soon as the supplier introduces its standard price adjustment clause from the framework-agreement template, it is standard terms and is measured against Section 307 BGB, even in a relationship between two businesses.

An individually negotiated agreement presupposes genuine negotiation. The user must have seriously put the core content that departs from the statutory model up for discussion and granted the contractual partner freedom to shape it. Merely negotiating the level of a percentage is not enough under the case law.

Anyone who wants to push through a demanding clause with a broad adjustment mechanism should therefore document the negotiation process, for example through negotiation minutes, visible changes to the draft and alternative wording proposals. For framework agreements that carry an entire supply relationship, this effort is worthwhile because it removes the clause from the strict standard-terms review.

How do you calculate the price adjustment? A worked example

A supplier delivers steel components at the initial price P₀ = 100,000 € per lot. The clause corresponds to the sample above: fixed share 40 %, steel share 45 %, labour share 15 %. At conclusion of the contract both indices stand at 100 (M₀ = 100, L₀ = 100).

Case 1, rising costs. At the settlement date the steel index has risen to 118 (plus 18 %), the labour index to 105 (plus 5 %).

P₁ = 100,000 × (0.40 + 0.45 × 118/100 + 0.15 × 105/100)

P₁ = 100,000 × (0.40 + 0.531 + 0.1575)

P₁ = 100,000 × 1.0885 = 108,850 €

The adjustment amounts to plus 8.85%. It is above the threshold of 3 % and below the cap of 10 %, so it takes full effect. The fixed share has dampened the increase: although steel became 18 % more expensive, the price rises by only just under 9 %, because 40 % of the price does not move.

Case 2, cap applies. If the steel index jumps to 140 (plus 40 %), the formula yields 0.40 + 0.63 + 0.1575 = 1.1875, that is plus 18.75%. The cap limits the adjustment to plus 10 %, and the price rises to 110,000 €. The residual risk is borne by the supplier, a deliberately set negotiation point.

Case 3, falling costs. If the steel index falls to 85 (minus 15 %) with the labour index unchanged at 100, the result is 0.40 + 0.3825 + 0.15 = 0.9325, that is minus 6.75%. The threshold is exceeded, the symmetry takes effect, and the price falls to 93,250 €. This case in particular shows why the duty to reduce the price is not a concession but a condition of enforceability.

Which mistakes make price adjustment clauses unenforceable?

Price adjustment clauses rarely fail because of the commercial concept; they fail because the mechanism is poorly drafted. A one-sided provision allowing only price increases is particularly vulnerable. Cost reductions must be passed on using the same benchmark and in the same accounting period. Vague reference points such as a change in 'operating expenses' or an adjustment at a party's 'reasonable discretion' are equally problematic. A robust clause needs specific, objectively verifiable factors, usually a precisely identified official index.

The weighting must also reflect the supplier's actual cost structure. If the material share is set higher than the underlying calculation supports, the clause becomes a concealed profit lever. The same problem arises where the entire price follows a single index although only part of the supplier's costs are affected. A realistic fixed share prevents overcompensation. The chosen index must also be relevant: only a factor that directly affects the supplier's own costs can support a cost-element clause under section 1(2) no. 3 PrKG.

Finally, the mechanism must remain transparent. At the time of contracting, the customer must be able to understand when an adjustment will occur, which data will be used and how far the price may move. If the formula, base value or settlement date is left open, the clause is likely to breach the transparency requirement in section 307(1), sentence 2 BGB.

Note the legal consequence under Section 8 PrKG: a clause that infringes the PrKG does not become void retroactively but becomes unenforceable only upon a final and binding determination of the infringement, and with effect for the future. A breach of Section 307 BGB, by contrast, leads to unenforceability from the outset, with the result that the original fixed price applies.

The standard-terms review operates here alongside the PrKG. Recent case law confirms this line: in 2026 the Federal Court of Justice treated an opaque index clause as retroactively unenforceable through standard-terms law and allowed already-paid excess amounts to be reclaimed (decision on a commercial lease; the review standard of Section 307 BGB nevertheless applies in the B2B supply business as well).

How do procurement and sales negotiate the clause?

Procurement and sales negotiate the same core levers, but assess them from opposite perspectives.

From the procurement perspective, a price adjustment clause is acceptable only if the exposure remains clearly contained. A sufficient fixed share ensures that only genuinely volatile cost components move. A threshold filters out minor fluctuations, a cap protects the budget against extreme swings and symmetry ensures that falling raw-material or energy costs are passed through as well. Procurement also needs a right to verify the index values used. Most importantly, the proposed material, energy and labour weightings should be checked against the supplier's actual cost structure; an inflated variable share is the most common hidden price driver.

From the sales perspective, the clause protects the margin against procurement shocks without building a blanket risk premium into the price. Its strongest argument is objective predictability: the adjustment follows a published index and agreed formula rather than the supplier's discretion. Sales should likewise avoid setting the fixed share unrealistically low, as an over-protective clause is easier to challenge. A moderate cap and a genuine obligation to pass on reductions are not merely concessions; they improve commercial acceptance and legal robustness. For long-term framework agreements, the parties should also document which elements were individually negotiated.

The interests lie closer together than it seems at the negotiating table. A transparent, symmetrical and capped clause distributes the raw-material risk predictably between the parties instead of shifting it one-sidedly. That is at the same time the clause that holds up in court.

Price adjustment clauses in construction contracts and public procurement

Construction is a special field. Under Section 9(9) VOB/A, price adjustment clauses may exceptionally be provided for in public construction contracts where material changes in the basis of price calculation are to be expected but their extent and timing remain uncertain and go beyond the usual calculation risk. When the material market swung in 2022 in the wake of the war in Ukraine, the Federal Ministry for Housing, Urban Development and Building introduced, by decree of 25 March 2022, a temporary material price adjustment clause for federal construction. The mechanism was extended several times and expired on 30 June 2023 after prices had largely stabilised.

For application in federal construction, typical conditions apply that also serve as guidance for the private sector: the affected material cost share must carry noticeable weight (the federal framework works with triviality and materiality thresholds in the low single-digit percentage range), a longer period must lie between offer and execution (regularly several months), and the expected price change must reach a special extent. The principle remains the same as in the supply contract: a specific index, a clear calculation method, symmetry.