Stephen Schwarzman built one of the world’s largest private-equity firms, banked some of the biggest paydays in modern finance, and committed more than $1 billion to charity over his lifetime.

And the Blackstone cofounder and CEO traces the roots of his charitable giving to observing his grandfather.

“I remember being a young boy and watching my grandfather pack prosthetics, wheelchairs, clothes, books, and toys to send to children in Israel every month,” Schwarzman wrote in his 2020 Giving Pledge letter. “When I asked him why, he explained that it was not only his obligation, but also his privilege to help others in need.”

The Giving Pledge is a commitment for ultrawealthy individuals to give away the majority of their wealth; other signatories include MacKenzie Scott, Warren Buffett, Mark Zuckerberg, and more.

Schwarzman, who has donated at least $1 billion over his lifetime, also highlighted his father, who ran a store in Philadelphia, regularly extending credit to newly arrived immigrants.