EU General Court Upholds Booking/Etraveli Prohibition: Key Takeaways for Dealmakers

On September 9, 2026, the General Court of the European Union (GC) dismissed Booking Holdings’ (Booking) challenge to the European Commission’s (EC) 2023 prohibition of its proposed acquisition of Etraveli Group (Etraveli). The judgment in Booking Holdings v Commission (T-1139/23) is significant for the assessment of non-horizontal mergers, particularly acquisitions by dominant companies of businesses or assets in adjacent markets.

The GC endorsed the EC’s ability to pursue a novel “reverse leveraging” theory of harm, under which a position in an adjacent market where the acquirer is not dominant may be used to reinforce an existing dominant position in another market. This differs from a more traditional “leverage” theory, where a company uses a strong market position in one market to strengthen its position in another market.

The GC also confirmed that a significant impediment to effective competition (SIEC) may be established largely on qualitative evidence and despite a very small transaction-related market share increment. At the same time, the judgment contains an important limiting principle: strengthening a dominant position does not, by itself, establish an SIEC. The EC must still demonstrate that the transaction is likely to significantly impede effective competition.

The judgment comes as the EC is finalising its revised Merger Guidelines. The draft revised Merger Guidelines expressly identify “entrenchment of a dominant position” as a separate theory of harm and cite Booking/Etraveli as an example involving the acquisition of an important customer-acquisition channel. The EC expects to complete the Guidelines review in Q4 2026.

Why did the EC prohibit the deal?

The EC found that Booking was dominant in EEA hotel online travel agency (OTA) services, while Etraveli was principally active in flight OTA services. The EC’s concern therefore did not depend on the elimination of significant head-to-head competition between the parties or acquiring control of an important input. Instead, the EC considered flights to be an important route for acquiring travel customers. The EC said that acquiring Etraveli would allow Booking to grow its flight offering rapidly and cross-sell hotel accommodation to those customers as part of a “Connected Trip” strategy. The EC concluded that this would reinforce network effects and enhance customer loyalty, increase barriers to entry and expansion and make an already strong position in hotel OTA services less contestable.

According to the EC, Etraveli’s significance therefore lay less in its standalone market position than in the role that flights played as an important customer-acquisition channel for Booking. The GC agreed that acquiring that channel could contribute to an ecosystem that rival hotel OTAs would find difficult to replicate.

Key takeaways from the judgment

• The existing Guidelines are not exhaustive, and reverse leveraging is a permissible theory of harm. The GC held that the 2008 Non-Horizontal Merger Guidelines do not prevent the EC from addressing new competitive concerns, including in digital markets, or from relying on leverage from a non-dominant adjacent market to reinforce an existing dominant position. In Booking/Etraveli, the strategically important asset was a flight customer-acquisition channel that (according to the EC) Booking did not already dominate, but wanted to move further into.
• Cross-selling and one-stop-shop convenience do not immunize a transaction from merger-control scrutiny. The GC rejected Booking’s argument that it was engaging in “competition on the merits.” The GC found that in merger control, the relevant question is the effect of the transaction on the structure of competition, even where the transaction may facilitate cross-selling or offer customers the convenience of a one-stop shop.
• Small market-share increments are not a safe harbour. The GC accepted that the transaction-related increase in Booking’s hotel OTA share could be only a few tenths of a percentage point. But it found that even a small increment can matter where the market is characterised by strong network effects, there is a significant gap between the dominant firm and its competitors, and the acquisition contributes to an ecosystem that competitors would find difficult to replicate.
• Contestability, not just current rivalry, is central. The prohibition survived because the transaction could make the dominant position the EC found to exist in hotel OTA less contestable and contribute to the consolidation and perpetuation of what the EC said was already a low level of competition. This is arguably the judgment’s most important substantive point.
• Qualitative evidence can carry substantial weight, but the evidentiary standard remains. The GC confirmed that an SIEC may be established on qualitative evidence, with or without quantitative support, provided the overall evidence is sufficiently cogent and consistent, takes account of the relevant evidence and supports the conclusions drawn from it.
• Strengthening dominance does not automatically establish an SIEC. The GC expressly distinguished between strengthening a dominant position and showing that the strengthening significantly impedes effective competition. The EC must still prove the latter.
• The counterfactual and efficiencies challenges also failed. The GC rejected Booking’s challenge to the EC’s counterfactual and upheld the EC’s conclusion that Booking’s claimed efficiencies were insufficient to offset the expected negative effects of the transaction.

What does this mean for businesses?

For companies contemplating transactions in concentrated markets, particularly those involving platforms, ecosystems or businesses with a strong incumbent position, the practical implications extend beyond digital markets:

• Look beyond horizontal overlaps. A target that does not itself have a dominant position may still attract scrutiny if it provides strategically important access to customers, data, technology, intellectual property, infrastructure or another capability that could reinforce the acquirer’s position in its core market. The draft revised Merger Guidelines expressly identify these types of assets in their entrenchment framework and cite Booking/Etraveli for customer acquisition channels.
• Assess contestability, not just market-share increments. Evidence on network effects, customer switching and multi-homing, alternative routes to customers, entry and expansion, and the counterstrategies available to rivals may be as important as traditional concentration measures. This is particularly so where the acquirer is already found to be dominant.
• Internal documents are important. Ordinary-course materials explaining that an acquisition will accelerate customer acquisition, expand an ecosystem, increase loyalty, reinforce network effects or accelerate expansion are important evidence. Businesses should ensure that transaction documents accurately explain both the strategic rationale and the competitive constraints that will remain after closing.

Develop the benefits case early. The judgment does not mean that one-stop shopping, product integration or the combination of complementary assets is inherently anticompetitive. But those benefits do not automatically defeat an entrenchment theory. Where efficiencies are material to the competitive assessment, parties should be prepared to demonstrate early that they are verifiable, merger-specific and likely to benefit customers — an approach that is also central to the EC’s draft revised Merger Guidelines.

Importantly, the judgment should not be read as making every ecosystem or complementary acquisition by a large company problematic. The EC’s proposed entrenchment framework itself focuses on an existing dominant position; an acquired asset connected to the core market and circumstances in which control of that asset reduces future contestability. The significance of the judgment is that, where those conditions are present, a limited conventional overlap or market-share increment may offer less comfort than parties might otherwise expect.

Booking has said that it disagrees with the outcome and is reviewing the judgment and a possible appeal to the Court of Justice.