X0101 EFFECT 33 LIVE 2018-07-20 0001710607-18-000061 485APOS 0001710607 AMERICAN CENTURY ETF TRUST 333-221045 S000062301 American Century Quality Diversified International ETF C000202058 American Century Quality Diversified International ETF S000062302 American Century STOXX U.S. Quality Growth ETF C000202059 American Century STOXX U.S. Quality Growth ETF