When must I inform a reporter about the assessment?

Three months from the acknowledgement of receipt, not from the report

The three-month period begins when the acknowledgement of receipt is sent, not when the report is received. This distinction is not merely cosmetic: the acknowledgement of receipt itself must be sent within seven days, and only from that sending date does the three-month period for feedback begin to run. If a report is received on a Monday and the acknowledgement is sent only on the last day of that week, this also shifts the end of the three-month period accordingly.

What the feedback must contain is information about the assessment of the report and about any follow-up steps — not necessarily a final determination about exactly what happened or who was right. A reporter must be informed within the period where the case stands: whether an investigation has been started, whether a follow-up step is planned, or whether the report was not pursued for a specific reason. This division — seven days for the acknowledgement, three months for the feedback, calculated from the acknowledgement — applies both to employers falling under the Dutch Whistleblower Protection Act and to employers falling under the German Hinweisgeberschutzgesetz. For organisations active in both countries, this is a welcome alignment: the same calculation rule in two separate laws.

Where this is set out: Article 9 Directive, Article 2 Whistleblower Protection Act, § 17 HinSchG

EU Directive 2019/1937 provides in Article 9 that member states must establish a feedback period of at most three months in their national legislation. The Netherlands has implemented this in Article 2, paragraph 2, point (i) of the Whistleblower Protection Act, in which the three-month period is explicitly linked to the sending of the acknowledgement of receipt in point (h) of the same paragraph. Germany has established the same linkage in § 17(2) Hinweisgeberschutzgesetz, directly following the seven-day period for the acknowledgement of receipt in § 17(1) No. 2.