$80 billion and rising: Clay Robbins’ steady hand and the runaway success of blockbuster drugs for diabetes and weight loss—Zepbound and Mounjaro-elevate endowment to North America’s largest private foundation

In a philanthropic world often defined by headline-grabbing pledges and tech-fueled moonshots, Clay Robbins has charted a different course—quiet, deliberate, and profoundly local.

And now, under his stewardship, Lilly Endowment Inc. has become the largest private foundation in America, with assets nearing $80 billion.

The surge stems from the runaway success of Eli Lilly & Co.’s blockbuster drugs for diabetes and weight loss—Zepbound and Mounjaro—which have not only transformed lives but also transformed the fortune of the Endowment, which holds over 96 million shares of Lilly stock. In 2024 alone, its assets rose 29 percent, and its required giving for 2025 is projected to exceed $3.6 billion.

For Robbins, who has led the Endowment since 1999, the moment is not about surpassing the Gates Foundation in size—it’s about stewardship. “Our role is to strengthen communities and invest in human dignity, not to chase headlines,” he’s said in past conversations.

Founded in 1937 by members of the Lilly family, the Endowment has long had a signature philanthropic footprint: rooted in Indiana, resonant across the nation, with signature initiatives in religion, education, and community development.

Robbins has honored that legacy with a calm precision, helping funnel billions into initiatives that uplift theological education, reinvigorate Christian congregational life, and support economic opportunity in underserved neighborhoods, particularly throughout Indiana.

This remarkable moment also raises a broader point about how meaningful influence works: sometimes it’s not through grandstanding, but through patient capital, long-standing relationships, and an enduring commitment to a place.

“It’s been a good time to be a charity in Indiana,” said FoundationMark’s John Seitz. But more than that, it’s been a good time to witness philanthropy done with quiet resolve and deep responsibility.

In a sector so often defined by the new, Robbins reminds us of the power of legacy, discipline, and staying true to purpose. And as Lilly Endowment prepares to scale its impact, its greatest asset may not be its billions but the steady, values-driven leadership guiding them.