A foreign fidelity and surety company shall not incur in behalf or on account of any one person, partnership, association, or corporation a liability for an amount larger than one-tenth of its total admitted assets, after deducting from such liability amounts reinsured in other companies authorized to do business in this State, unless it shall be secured from loss thereon beyond that amount by suitable and sufficient collateral agreements of indemnity, by deposits with it in pledge, or conveyance to it in trust for its protection, of property equal in value to the excess of its liability over such limit, or, in case such liability is incurred in behalf or on account of a fiduciary holding property in a trust capacity, by such deposit or other disposition of a suitable and sufficient portion of the estate so held, that no further sale, mortgage, pledge, or other disposition can be made thereof without such company's approval except by the decree of a court having proper jurisdiction.