(1) A letter of credit may not be used to reduce any liability for reinsurance ceded to an unauthorized assuming insurer in financial statements required to be filed with this department unless an acceptable letter of credit with the filing ceding insurer as beneficiary has been issued on or before the date of filing of the financial statement. Further, the reduction for the letter of credit may be up to the amount available under the letter of credit but no greater than the specific obligation under the reinsurance agreement which the letter of credit was intended to secure.