Democratic presidential candidate and former Vice President Joe Biden this week released several years of income tax returns, probably hoping the story would be that he did so and President Trump has not.

However, Richard Rubin from the Wall Street Journal found a much more interesting nugget: in 2017 and 2018, Joe Biden and his wife ran $13 million of profits through two subchapter-S corporations. In so doing, they avoided $500,000 in Social Security and Medicare taxes they would have paid if they instead reported the income as sole proprietors directly on their 1040 income tax returns.