Data is a success factor for digital platforms and the core of their business model. The rationale behind this is that data allows for improving the matching process between users which creates value for the platform. Since some large platforms act as gatekeepers, the Digital Markets Act (DMA) was introduced in Oct. 2022 to ensure a fairer business environment. This paper analyzes the consequences of the 4th obligation of Art. 5 of the DMA. Using a simple game theory model, we analyze the changes in incentives for different business models implied by the obligation. In fact, the obligation increases the incentives for the business users to use the platform because new customers can be acquired. The incentives for establishing an independent web shop also increase. Furthermore, more data is available, both for the platform and the business users. However, the platform is likely to benefit more from the increase in data collection and is incentivized to become vertically integrated. Finally, the fees imposed by the platform may increase.

数据是数字平台的成功因素，也是其商业模式的核心。其背后的理由是数据可以改善用户之间的匹配过程，从而为平台创造价值。由于一些大型平台充当把关人的角色，2022年10月推出了《数字市场法案》（DMA），以确保更公平的商业环境。本文分析了第四条义务的后果。5 DMA。使用简单的博弈论模型，我们分析了义务所隐含的不同商业模式的激励变化。事实上，这一义务增加了企业用户使用该平台的动力，因为可以获得新客户。建立独立网上商店的动力也在增加。此外，平台和业务用户都可以获得更多数据。然而，该平台可能会从数据收集的增加中受益更多，并有动力进行垂直整合。最后，平台收取的费用可能会增加。