Private foundation is an institution with a very special status. They are tax exempt private organizations yet they are still allowed to invest into for profit companies. Foundations can hold corporate stocks and bonds and generate revenue this way.

There is only one major condition they have to fulfill to keep their tax exempt status - and that is to donate 5% of foundation’s total assets on annual basis. So when you hear a billionaire donating their wealth to charity and it’s going through a foundation, up to 95% of it can go into profitable investments. In practice, all foundations’ assets in the US amount to more than $1 trillion. Yet, they donated only $90.88 billion in 2021.