Section 1. Section 28(A)(3)(a) of Republic Act No. 8424, otherwise known as the National Internal Revenue Code of 1997, as amended, is hereby further amended to read as follows:

"SEC. 28. Rates of Income Tax on Foreign Corporations. —

"(A) Tax on Resident Foreign Corporations. —

"(1) xxx

"(2) xxx

"(3) International – Carrier. — An international carrier doing business in the Philippines shall pay a tax of two and one-half percent (2 1/2 %) on its ‘Gross Philippine Billings’ as defined hereunder:

"(a) International Air Carrier. — ‘Gross Philippine Billings’ refers to the amount of gross revenue derived from carriage of persons, excess baggage, cargo, and mail originating from the Philippines in a continuous and uninterrupted flight, irrespective of the place of sale or issue and the place of payment of the ticket or passage document: Provided, That tickets revalidated, exchanged and/or indorsed to another international airline form part of the Gross Philippine Billings if the passenger boards a plane in a port or point in the Philippines: Provided, further, That for a flight which originates from the Philippines, but transshipment of passenger takes place at any part outside the Philippines on another airline, only the aliquot portion of the cost of the ticket corresponding to the leg flown from the Philippines to the point of transshipment shall form part of Gross Philippine Billings.

"(b) International Shipping. — ‘Gross Philippine Billings’ means gross revenue whether for passenger, cargo or mail originating from the Philippines up to final destination, regardless of the place of sale or payments of the passage or freight documents.

"Provided, That international carriers doing business in the Philippines may avail of a preferential rate or exemption from the tax herein imposed on their gross revenue derived from the carriage of persons and their excess baggage on the basis of an applicable tax treaty or international agreement to which the Philippines is a signatory or on the basis of reciprocity such that an international carrier, whose home country grants income tax exemption to Philippine carriers, shall likewise be exempt from the tax imposed under this provision.

"x x x."