Risk controlling in the real estate sector has gained significant importance in recent years. One challenge is to recognize market trends early and adequately assess their impact on a real estate portfolio. Rupert Späth uses a self-developed crawler to relate data from properties to be managed to offers from real estate portals. Additionally, he expands the controlling basis by transferring data from existing properties and considering the forecast of tenant behavior through probabilistic simulation. Finally, the aggregation and interpretation of this data is addressed, with particular attention to the company's liquidity.