No insurer transacting title insurance in this State shall expose itself to any one risk in an amount exceeding fifty per cent of the aggregate amount of its total capital and surplus and its reserves other than its loss or claim reserves. As used in this section, the words “any one risk” mean the risk or hazard attaching to or arising in connection with any one piece or parcel of property, whether or not the policy insures other property. Any risk or portion of any risk which has been reinsured as authorized in this part shall be deducted in determining the limitation of risk prescribed in this section.