Forgotten rent indexing? You can do this

Often the lease of business premises contains an indexation clause. Under this, the rent can be indexed periodically - usually annually. Usually this is done on the basis of inflation. How the indexation of rent exactly how it works, you can read here. In the article below, we discuss tenancy law lawyer Robert van Ewijk what happens when the landlord has forgotten for years to demand payment of indexed rent. Is the landlord then out of luck? Or has the tenant underpaid for years and is now in arrears?

What does the agreement say about indexation of rent

Whether rent indexation may still be retroactive depends on how the clause in the lease is worded. If it states that the rent each year “may” be indexed, then this indicates that another action by the landlord is required. But if it says that the rent will be indexed annually “becomes” indexed and it is also clearly described how the indexed rent should be calculated, then it is defensible that the higher indexed rent automatically applies. In the most recent model lease agreements of the ROZ, this avoids any doubt. In fact, it states:

“An adjusted or indexed rent is due and payable even if no separate notice of the adjustment is given to the tenant.”

This is stated in the ROZ model for retail space in Article 4.7.3 and for the office space model in Article 4.5.3.

Case law on forgotten rent indexing: indexing still allowed

Despite the fact that the indexation clause may provide that the rent is automatically indexed and thus the higher rent has become automatic, some judges find it unreasonable that:

1. the tenant suddenly has to start paying rent much higher than anticipated;
2. who also has to start catching up on past backlogs (sometimes several years), and;
3. then also legal commercial interest owed.

Therefore, claims by landlords that go back too long are regularly barred. Judgments in the courts have therefore varied regarding landlords who not only want to index the rent retroactively, but also demand payment of arrears caused by the indexations. I discuss some relevant judgments below. First a calculation example.

Calculation example forgotten rent indexing

Suppose the initial rent was €10,000 per year. Under the terms of the lease, the rent increased to €12,000 in year two. In year three, the rent is €14,000. All these years the tenant has paid the initial rent. In year four, the landlord wakes up. He calculates that the rent in year four should be €16,000,- and notifies the tenant that from then on he has to start paying that new rent. Furthermore, he demands payment of the arrears: €6,000 in total: €2,000 for year two and €4,000 for year three.

Case law: retroactive indexing and claiming late payments

The Amsterdam Court of Appeal ruled on March 14, 2017 (ECLI:NL:GHAMS:2017:836) that the application of indexation does not require any action by the landlord. The tenant accepted that automatic indexation. The tenant's position that its business operations were jeopardized by the increase was dismissed by the Court of Appeals: the tenant has its own responsibility to keep track of the amount of rent owed. The tenant had to start paying not only the higher rent, but also the arrears caused by not paying the indexed rent. Legal interest on these was also awarded.

Landlord can still index and tenant must pay arrears

A few years earlier, the same court also reached that judgment. In the judgment of the Amsterdam Court of Appeal April 10, 2012 (ECLI:NL:GHAMS:2012:BW7821) it was held that the landlord's claim to the overdue indexation amount (to the extent not subject to statute of limitations) and for future lease installments at the full indexed rent, does not violate reasonableness and fairness. Again, it was held that the tenant had a personal responsibility to ensure that the correct amount of rent would be paid.

However: conflict with reasonableness and fairness and disadvantage

The Overijssel District Court in 2016 (ECLI:NL:RBOVE:2016:4951) to a different verdict. It concerned the lease of a supermarket in Borne, with Nettorama as landlord. In that case, the rent had never been indexed between 1984 and 2015. Furthermore, the tenant had repeatedly received final bills from the landlord. Nettorama then wanted to index after 32 years, and also wanted satisfaction of the arrears in payment caused by the indexation. The rent would go up by 700%.

The cantonal court finds apparent that there is estoppel. By sending annual final statements, the landlord had created the impression that it would no longer claim the indexation. Awarding the indexation retroactively was therefore contrary to reasonableness and fairness. Incidentally, an interesting aspect of that ruling is that the court also considered that Nettorama had deprived its tenant of the opportunity, to have rent reviewed by the court. After all, if annual indexing had occurred, the tenant would have found (in a timely manner) that the rent had increased, and could have asked the court to set the market price.

Landlord keeps sending invoices for the non-indexed amount: estoppel?

However, continuing to send invoices does not always lead to estoppel. This was discussed in a judgment of (again) the Amsterdam Court of Appeal (ECLI:NL:GHAMS:2007:BG5434) . The landlord in that case repeatedly sent invoices for rent that was too low - not indexed. The case involved a rent dispute between Maresca B.V. as lessee and the Municipality of Utrecht as lessor. Maresca reproached the municipality for failing to mention in a meeting the indexations that had not been implemented and the resulting arrears. It also indicated that the landlord had continued to invoice the ‘old’ rent for years.

Yet, according to the court, there was no estoppel. Despite the municipality's silence and erroneous billing, the tenant should not have trusted that the landlord would permanently waive the indexations. That might have been different had the landlord been aware of its mistake. The circumstances outlined by Maresca, do not demonstrate this. Therefore, still claiming the rent arrears and claiming the indexed rent, are not contrary to reasonableness and fairness.

Parties deviated from indexation clause

It may also be the case that the parties have explicitly (or implicitly) deviated from the contractual agreements on rent indexation. This was the case in a case in which the Midden Nederland District Court ruled on February 19, 2025 (ECLI:NL:RBMNE:2025:685). In that case, it was agreed at some point that the landlord would “the coming years” would not claim rent indexations. Given the wording of that agreement, the court found that it applied indefinitely. Therefore, the landlord could not claim contractual rent price indexation.

Can the claim under forgotten rent indexation be time-barred?

The law states that a claim for payment of sums of money is time-barred after 5 years (Art. 3:308 BW). By that statute of limitations the landlord can therefore no longer demand payment of rent arrears after five years. Incidentally, the statute of limitations does not prevent indexing over a period going back more than five years. To calculate the current rent, one can therefore go back a long time. The Amsterdam Court of Appeal, among others, ruled this on March 14, 2017 (ECLI:NL:GHAMS:2017:836). This is because indexing works by operation of law, and does not require an expression of will.

Specialized rental law attorney in dispute over rent indexation

The main rule seems to be that the landlord may still index the rent retroactively, unless there are special circumstances. Furthermore, in principle, the overdue rent that would have been paid if indexing had been done immediately may be claimed. This is because the tenant has his own responsibility to pay the correct rent. However, everything must remain ‘within reason’. Lexys' attorney specializing in rent law successfully assists both tenants and landlords in disputes involving rent indexation. Take contact at if you want to know more.