National Internal Revenue Code (NIRC)
Section 198. Stamp Tax on Assignments and Renewals of Certain Instruments. - Upon each and every assignment or transfer of any mortgage, lease or policy of insurance, or the renewal or continuance of any agreement, contract, charter, or any evidence of obligation or indebtedness by altering or otherwise, there shall be levied, collected and paid a documentary stamp tax, at the same rate as that imposed on the original instrument.