The Commissioner shall not authorize an alien insurer to transact insurance in this State unless it makes and thereafter continuously maintains on deposit in this State through the Commissioner, or in another state, a surplus of assets in cash or securities eligible for such deposit under the laws of this State or such other state of a value not less than the combined capital and surplus initially required of a like foreign insurer transacting like kinds of insurance in this State. The deposit shall be held in trust for the benefit and security of all the insurer's policyholders and creditors in the United States or of all the insurer's policyholders in the United States.