What happens if a contract is silent?

When a contract is silent, the law supplements the agreement. Under Dutch law via Article 6:248 of the Dutch Civil Code (reasonableness and fairness); internationally via the CISG, English implied terms, or local law. In our practice, we see entrepreneurs who assume that only what is written down applies. The reality is different: in every dispute, the law supplements what the parties have not explicitly regulated — often with unexpected outcomes.

What is the legal problem?

If a contract is silent, supplementary law comes into effect. This can be mandatory or regulatory in nature. Supplements arise from statutory rules, customs, reasonableness and fairness, or the parties' intent. The result is often not what a party expected. Internationally, supplementation varies widely: CISG, common law, civil law, and trade practices provide supplementation differently.

What does the law say?

Under Dutch law, Article 6:248 paragraph 1 of the Dutch Civil Code supplements contracts with reasonableness and fairness. Article 6:248 paragraph 2 of the Dutch Civil Code allows for derogatory effect. The Vienna Sales Convention contains detailed supplementary rules for sales in Articles 14-89 of the CISG: offer, acceptance, complaint periods, and remedies. Article 39 of the CISG provides for a complaint period 'within a reasonable time after discovery, at the latest two years after delivery'.

Under English law, implied terms apply under the Sale of Goods Act 1979 (Section 14 for satisfactory quality) or by judicial supplementation under the Marks & Spencer v BNP Paribas test (2015). Local trade practices may provide supplementation under any system. Trade associations publish standard terms and conditions that are considered customary.

What risks do companies face?

Additions can lead to shorter or longer periods than you expected. Statutory standard warranties can extend your liability. Unknown complaint periods under Section 39 CISG (within a reasonable time after discovery) can cause your right to lapse. Local customs you are unaware of can be used against you. What the contract does not regulate, the court regulates — often in a way that does not align with your expectations.

Practical example from our practice

We advised a Dutch supplier who sold to an Italian buyer without a complaint period in the contract. The buyer complained about a defect after 18 months. Under Section 39 CISG, the period 'within a reasonable time after discovery, at the latest two years after delivery' had not yet expired. Upon renegotiation, we incorporated our own complaint period of 14 days following discovery, with the explicit exclusion of the CISG under Article 6 of the CISG. Subsequent late complaints were rejected without dispute.

What can you do?

Anticipate what the contract does not regulate and exclude additions where necessary. Deliberately include or exclude the Vienna Sales Convention under Article 6 of the CISG. Explicitly regulate complaint periods, complaint procedures, and the burden of proof. Research local trade practices in your key markets. Use a watertight contract for critical components. Have your standard contract reviewed by an international trade lawyer for each market. See also our article on Which law applies to your international contract?