Pub. L. 91-373, tit. III, sec. 302
INCREASE IN WAGE BASE.
SEC. 302. INCREASE IN WAGE BASE. Effective with respect to remuneration paid after December 31, 1971, section 3306(b)(1) of the Internal Revenue Code of 1954 is amended by striking out “$3,000” each place it appears and inserting in lieu thereof “$4,200”.