How important is human capital at the top of the U.S. income distribution? Most top income is non-wage income, a primary source of which is private "pass-through" business profit. These profits—which can include labor income disguised for tax reasons—accrue to working-age owners of closely-held, mid-market firms in skill-intensive industries. Pass-through business profit falls by three-quarters after owner retirement or premature death. Classifying three- quarters of pass-through profit as human capital income, we find that the typical top earner derives most of his or her income from human capital, not financial capital. Our approach also raises the overall top 1% labor share in 2014 from 45% to 56%. Growth in pass-through profit is explained by both rising productivity and a rising share of value added accruing to owners.