40 Pa. Stat. § 181
Any insurance company, association, or exchange, incorporated or organized under the laws of this Commonwealth, desiring to transact business in other States, the laws whereof require that such company, association, or exchange shall first deposit securities of a designated value with the Insurance Commissioner or other proper officer of this Commonwealth in trust and for the benefit of all its policyholders, or any insurance company or association of a foreign government desiring to make the deposit required of foreign companies or associations in order to transact business in the United States, is hereby authorized to deposit with the Insurance Commissioner securities for such an amount as the laws of such other States designate, or as the laws of this State require for foreign companies or associations. If the Insurance Commissioner is satisfied that such securities are worth the required amount, it shall be his duty to receive the same, or those given in exchange therefor as hereinafter provided, for the purpose aforesaid. Upon the written request of said insurance company, association, or exchange, the Insurance Commissioner shall certify, under his hand and official seal, to the proper officer of such other State or States or of the United States Government, wherein said insurance company, association, or exchange may desire to transact business, that said company, association, or exchange has deposited with him securities, giving the items of kind thereof, and that he is satisfied they are worth the sum designated by the laws of such other State or States, or required by the United States Government.
40 P.S. § 181