EFFECTIVE DATE OF PART VI.

SEC. 464. EFFECTIVE DATE OF PART VI. The amendments made by sections 461 and 463 shall take effect on the first day of the first month which begins more than ten days after the date of the enactment of this Act. In the case of the year beginning July 1, 1951. where the trade or business on which the tax is imposed was commenced prior to the first day of the month specified in the preceding sentence, the increase in tax resulting from such amendments shall be reckoned proportionately from the first day of such month to and including the thirtieth day of June following and shall be due on, and payable on or before, the last day of the month specified in the preceding sentence.