Donald Trump’s pledge to give Elon Musk a top job could make the billionaire CEO eligible for a special tax benefit worth tens of billions of dollars.

Thanks to a provision buried in the tax code, Elon Musk could reap one of the largest personalized tax breaks in American history if former President Donald Trump wins the 2024 election and fulfills his pledge to appoint Musk to a top government post, according to tax and ethics experts’ review of long-standing statutes.

This special tax benefit — which is only available to federal officials — would be in addition to massive tax breaks Musk could reap if a new Trump administration furthercuts income and other taxes for billionaires.