Section 173National Internal Revenue Code of 1997 (Republic Act No. 8424), Sec. 173

Stamp Taxes Upon Documents, Loan Agreements, Instruments and Papers. - Upon documents, instruments, loan agreements and papers, and upon acceptances, assignments, sales and transfers of the obligation, right or property incident thereto, there shall be levied, collected and paid for, and in respect of the transaction so had or accomplished, the corresponding documentary stamp taxes prescribed in the following Sections of this Title, by the person making, signing, issuing, accepting, or transferring the same wherever the document is made, signed, issued, accepted or transferred when the obligation or right arises from Philippine sources or the property is situated in the Philippines, and the same time such act is done or transaction had: Provided, That whenever one party to the taxable document enjoys exemption from the tax herein imposed, the other party who is not exempt shall be the one directly liable for the tax.