April 2021 Chemical Activity Barometer Index Continues To Improve from the American Chemistry Council The Chemical Activity Barometer (CAB), a leading economic indicator created by the American Chemistry Council (ACC),rose 0.7% in April on a three-month moving average (3MMA) basis following a 1.1% increase in March and a 0.9% gain in February. On a year-over-year (Y/Y) basis, the barometer rose 12.0% in April (3MMA). The unadjusted data show a 0.3% increase in April following a 1.4% gain in March. The diffusion index reached 100% in April. The diffusion index marks the number of positive contributors relative to the total number of indicators monitored. The CAB reading for March was revised downward by 0.35 points and the reading for February was revised downward by 0.58 points. The April data are provisional and subject to revision.