Where the information necessary for calculating the group solvency of an insurance or reinsurance undertaking, concerning a related undertaking with its head office in a Member State or a third country, is not available to the supervisory authorities concerned, the book value of that undertaking in the participating insurance or reinsurance undertaking shall be deducted from the own funds eligible for the group solvency.
In that case, the unrealised gains connected with such participation shall not be recognised as own funds eligible for the group solvency.