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 4 th 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.