We describe the implementation of an enterprise monitoring system that builds on an ontology-based information extraction (OBIE) component applied to heterogeneous data sources. The OBIE component consists of several IE modules--each extracting on a regular temporal basis a specific fraction of company data from a given data source--and a merging tool, which is used to aggregate all the extracted information about a company. The full set of information about companies, which is to be extracted and merged by the OBIE component, is given in the schema of a domain ontology, which is guiding the information extraction process. The monitoring system, in case it detects changes in the extracted and merged information on a company with respect to the actual state of the knowledge base of the underlying ontology, ensures the update of the population of the ontology. As we are using an ontology extended with temporal information, the system is able to assign time intervals to any of the object...