The Dutch Authority for Consumer and Market fined House of Tickets B.V. 270,000 euros on 22 May 2026 for deploying a purpose-built bidding algorithm to impersonate consumers in its own online auctions, manipulating prices across tens of thousands of transactions and sending deceptive follow-up offers to more than 33,000 people.

The decision, issued under case number ACM/26/201019, concerns conduct carried out on Ticketveiling.nl, a platform operated by Ticketveiling B.V. - a wholly owned subsidiary of House of Tickets. The platform ran online auctions for leisure outings, services, and products. According to the ACM, the platform used automated bidding software, referred to in the decision as biedbots, to participate in its own auctions and push prices toward predetermined minimum levels, all without disclosing to human participants that such software was active.

What the bots did and how they were concealed

Between 1 August 2024 and 1 December 2024, according to the ACM decision, Ticketveiling deployed biedbots across 71,420 auction lots on Ticketveiling.nl. The bots entered bids automatically. Their specific purpose, according to the regulator, was to reach a preset minimum price per lot - essentially a reserve price implemented through automated bidding rather than disclosed as a floor.

The concealment was technical and deliberate. According to the ACM decision, the bots operated under randomly assigned fictitious names generated by the system. These names were presented in the auction interface in exactly the same way as the names of genuine human participants, making them indistinguishable. To prevent pattern recognition, the platform deployed multiple distinct algorithms - called plotters in the decision - each with different bidding logic. A plotter determines how often bids are placed, when they are placed, and in what increments. Multiple plotters could run simultaneously within a single auction. The same fictitious name was also prevented from appearing twice in a row, reducing the chance that a participant would notice mechanical repetition.

Participants in the auctions had no way of knowing they were bidding against automated software. Nothing in the account creation process, the opt-in for follow-up offers, or the platform's terms and conditions disclosed the existence or use of biedbots, according to the ACM.

The follow-up offer and how it compounded the deception

The second violation identified in the ACM decision concerns what the platform called a lachende tweede aanbod - a "smiling second offer." When a bot won an auction lot, Ticketveiling sent an email to non-winning human participants offering them the same lot at the same final price.

According to the ACM, in the period from 1 August 2024 to 1 December 2024, these emails were sent to 33,027 non-winning participants following auctions that a bot had won. The emails stated that the recipient could purchase the item for the same price as the winner. They did not mention that the winning bidder was an automated system, that the auction had been used to reach a preset minimum price, or that the final price had been shaped by bot activity rather than genuine competitive demand between human participants.

According to the ACM, more than 1,000 recipients accepted this offer. The regulator found that these consumers may have made a different purchasing decision had they known the truth. With accurate information, they could have bought the product directly from the original supplier at a potentially lower price, or compared alternatives elsewhere.

The ACM classified this second practice as misleading under Article 6:193c of the Dutch Civil Code, which prohibits presenting factually incorrect or misleading information about price formation that causes or could cause the average consumer to take a transactional decision they would not otherwise have taken.

The ACM applied Article 8.8 of the Wet handhaving consumentenbescherming - the Consumer Protection Enforcement Act - which requires traders to comply with provisions of the Civil Code governing unfair commercial practices. Two specific provisions were engaged.

The first is Article 6:193g(v) of the Civil Code, which identifies as misleading a commercial practice that "fraudulently claims or gives the impression that the trader is not acting for purposes related to its trade, business, craft, or profession, or fraudulently poses as a consumer." The biedbots, operated by Ticketveiling in its own auctions under fake consumer identities, met this definition directly.

The second is Article 6:193c(1)(d), which prohibits factually incorrect or misleading information about price or how a price is calculated. The smiling second offer emails, which presented a bot-inflated price as the outcome of genuine competitive bidding, fell within this provision.

Both violations, according to the ACM, are attributable not only to Ticketveiling B.V. but also to its parent, House of Tickets B.V. The regulator noted that the two companies share the same address, that House of Tickets is the sole director and sole shareholder of Ticketveiling, and that the natural persons who hold ultimate ownership and director roles at House of Tickets were physically present and active on the Ticketveiling shop floor during the infringement period. House of Tickets had full knowledge of and effective control over Ticketveiling's conduct, and it profited from the results. The ACM therefore treated House of Tickets as a functional perpetrator of both violations.

To avoid doubling the financial penalty, the ACM chose to impose the fine solely on House of Tickets.

How the fine was calculated

The ACM's penalty policy categorises violations into bands. The two violations in this case - impersonating a consumer and misleading price presentation - fell into categories III and IV respectively under the Boetebeleidsregel ACM 2014, the authority's fine policy. The ACM applied the highest band.

Starting from an assessment of the seriousness of the conduct, the degree of culpability, and the circumstances of the infringement, the ACM set a base figure of 300,000 euros. Two factors then shaped the final number. First, the ACM noted that the violations lasted a relatively short time - four months - and that House of Tickets had stopped the conduct on its own initiative before the ACM investigation formally began. Second, House of Tickets and Ticketveiling cooperated with the regulator, admitted both violations in a written statement, and accepted the fine under a simplified settlement procedure. The ACM reduced the base figure by 10 percent for this cooperation, arriving at a final penalty of 270,000 euros.

The ACM investigation began in March 2025, triggered by internal intelligence reports and external signals including media coverage. Formal settlement discussions took place on 3 March 2026 and 17 April 2026. The decision was signed on 22 May 2026 by drs. M. Ridderbos, a board member of the ACM.

What this means for enforcement of algorithmic deception

The ACM has identified the digital market as a priority oversight area and specifically targets the misuse of algorithms by businesses. This case is notable because the deceptive mechanism was not a dark pattern in a user interface or a misleading label, but a purpose-built algorithm that faked human identity at the transaction level.

The case raises a practical enforcement question. The ACM penalty of 270,000 euros applies to conduct across 71,420 lots over four months. That works out to roughly 6.75 euros per affected auction lot. Whether this sum constitutes a meaningful deterrent depends on how long the bots were running before the investigation began, and what margin the inflated prices generated over the entire operating period of the platform.

Bot fraud in digital auction environments is not new territory. In the programmatic advertising sector, automated invalid traffic has been a persistent source of inflated costs for buyers, with estimates of wasted spend running into billions of dollars annually. The Ticketveiling case extends the same structural problem - automated software bidding against human participants without disclosure - into consumer e-commerce auctions, and shows that regulators are willing to use consumer protection law, not just advertising standards, to address it.

The ACM's enforcement of algorithm-driven deception sits within a wider pattern of European regulatory attention to how automated systems affect consumer decision-making. Regulators in Australia, Spain, and Ireland have each taken action in the first half of 2026 against misleading online practices, ranging from fake pricing and fraudulent discount claims to GDPR violations in digital identity verification.

For marketers and platform operators, the Ticketveiling case illustrates a specific legal risk: using an algorithm to impersonate a consumer in a competitive transaction environment is treated as a serious consumer law violation, not merely a technical policy breach. The ACM was explicit that it considers algorithm-mediated deception to be particularly serious, because it is designed, scalable, and invisible to the people it affects.

Timeline

  • October 2024 - ACM receives internal intelligence report (ACM/INT/523570) flagging concerns about Ticketveiling's practices
  • December 2024 - ACM receives supplementary intelligence report (ACM/INT/523571) and a record of consumer complaints covering December 2023 to December 2024
  • 1 August 2024 - 1 December 2024 - Period during which biedbots were deployed across 71,420 auction lots on Ticketveiling.nl, and smiling second offers sent to 33,027 non-winning participants
  • Before ACM investigation formally began - House of Tickets halted the biedbot conduct on its own initiative
  • March 2025 - ACM formally opens investigation into Ticketveiling, prompted by internal reports and external signals including media coverage
  • Early March 2026 - Ticketveiling and House of Tickets request simplified settlement procedure from ACM
  • 3 March 2026 - First formal discussion between Ticketveiling, House of Tickets, and ACM under simplified settlement procedure
  • 17 April 2026 - Second formal discussion between parties and ACM
  • May 2026 - Ticketveiling and House of Tickets submit written statement admitting both violations and accepting the fine
  • 22 May 2026 - ACM issues its decision, imposing a fine of 270,000 euros on House of Tickets B.V. (case number ACM/26/201019, document ACM/UIT/679013)

Summary

Who: House of Tickets B.V. and its subsidiary Ticketveiling B.V., operators of Ticketveiling.nl, an online auction platform for leisure products and services based in the Netherlands.

What: The Dutch Authority for Consumer and Market fined House of Tickets 270,000 euros for two violations of consumer protection law. The company deployed automated bidding software (biedbots) in its own auctions to drive prices toward preset minimums, while the bots posed as consumers under fictitious names. It also sent misleading follow-up purchase offers to over 33,000 people without disclosing that the auction prices had been shaped by bots rather than human competition.

When: The violations occurred between 1 August 2024 and 1 December 2024. The ACM investigation began in March 2025. The fine was issued on 22 May 2026.

Where: The conduct took place on Ticketveiling.nl, an online platform operated in the Netherlands. The ACM decision was issued from The Hague.

Why: The ACM found that both practices constituted unfair commercial practices under Dutch and EU consumer law - impersonating a consumer under Article 6:193g(v) of the Civil Code, and misleading price formation under Article 6:193c(1)(d). The authority treated algorithm-driven deception as particularly serious because it is purposefully designed, operates at scale, and is invisible to the consumers it affects. House of Tickets accepted both findings and a 10 percent discount on the base fine of 300,000 euros through a simplified settlement procedure.