From their About page:
“The Ludwig von Mises Institute was founded in 1982 as the research and educational center of classical liberalism, libertarian political theory, and the Austrian School of economics.“
“It is the mission of the Mises Institute to place human choice at the center of economic theory, to encourage a revival of critical historical research, and to advance the Misesian tradition of thought through the defense of the market economy, private property, sound money, and peaceful international relations, while opposing government intervention as economically and socially destructive.“
However, from their Donate page:
“The Mises Institute is a 501(c)(3) so contributions are deductible to the full extent the law allows. Ludwig von Mises Institute for Austrian Economics, Tax ID 52-1263436“
They hate government so much, they’re a government-sanctioned and regulated tax-exempt 501(c)(3) organization.
Now their justification, I’m sure, is that they’re serving the best interests of the Austrian School of economics by facilitating a way for the Institute and its supporters to remove as much from the government’s tax base as their operations and donors can afford.
However, a legal requirement of their tax-exempt status is compliance with regular reporting requirements and regulations of the Internal Revenue Service, the government agency whose forerunner was formed in 1862 during the Civil War administration of President Abraham Lincoln, which senior Mises fellow, Thomas DiLorenzo, aggressively attacks in his articles, and has aggressively attacked in his books, The Real Lincoln and Lincoln Unmasked.