The cornerstone of P.L. 115-97, known as the Tax Cuts and Jobs Act is the reduction of the maximum corporate tax rate of 35% to a flat 21%. For businesses being conducted as flow-through entities, such as S corporations, partnerships and sole proprietorships, the new law permits a deduction of up to 20% of qualified business income (QBI), effectively reducing the top tax rate paid by the individual owner from 37% to 29.6%.