NEW YORK, NY.- Melinda French Gates is leaving the behemoth foundation she and her former husband Bill Gates founded nearly a quarter-century ago to devote herself fully to her work on behalf of women and girls, which has been the focus of much of her recent philanthropy.

Her move, announced Monday, marks the end of an era for the Bill and Melinda Gates Foundation — henceforth known as the Gates Foundation — which she and her former husband founded in 2000 and transformed into a juggernaut that shook up the world of philanthropy and reshaped the fields of global public health and development.

“After careful thought and reflection, I have decided to resign from my role as co-chair of the Bill and Melinda Gates Foundation,” French Gates, 59, said in a post on X. She added that the foundation was “in strong shape,” and that it was the right time for her to move “into the next chapter of my philanthropy.” Her last day will be June 7.

French Gates will get $12.5 billion in resources to direct toward her philanthropic work. In a statement, she said she would use the money she was leaving with to “commit to my work on behalf of women and families.”

Already one of the world’s most influential female philanthropists, French Gates has long argued that the uplift of women benefits all of society. Her pivot to women’s rights and gender equality is likely to have a meaningful impact on the world of giving.

“It’s a milestone in the evolution of arguably the most important foundation of our time,” said Amir Pasic, the dean of Indiana University’s Lilly Family School of Philanthropy.

Pasic noted that French Gates’ potential contributions to women’s issues, from the $12.5 billion she is taking with her, could be influential. According to the school’s index, contributions to women’s and girls’ organizations in 2020 represented just 1.8% of all giving in the country.

So far, the main vehicle for French Gates’ work has been Pivotal Ventures, a firm she founded in 2015. Pivotal is not a foundation; rather, it is a limited liability company, a type of entity that can make grants to nonprofits as well as for-profit investments and engage in advocacy work. With dozens of employees, the firm, in Kirkland, Washington, targets issues such as paid family and medical leave and increasing female representation in politics, and invests in funds led by women.

In 2021, Pivotal was among the firms that called on the Biden administration to appoint a “caregiving czar.” French Gates has also worked with former first lady Michelle Obama and Mackenzie Scott, who is the ex-wife of Amazon founder Jeff Bezos and is also a philanthropist.

So far, Pivotal has made a commitment of $1 billion toward its causes; the new funds are likely to give it far more heft.

On X, Gates said he was “sorry to see Melinda leave,” but that she would “have a huge impact in her future philanthropic work.” He said French Gates was “instrumental” in helping shape the foundation’s vision, and that he remained “fully committed” to its work.

Gates, who is the world’s seventh-richest man and has an estimated net worth of $130 billion, according to Forbes, will become the sole chair of the Gates Foundation, Mark Suzman, the foundation’s CEO, said in a statement released Monday.

French Gates has “new ideas about the role she wants to play in improving the lives of women and families in the U.S. and around the world.” Suzman said. He added that she would be dedicating her time to altering the trajectory of “women’s rights rolled back in the U.S. and around the world” over the past few years.

When the foundation got its start, French Gates played more of a behind-the-scenes role, although she was engaged from the beginning. As her children grew older, she started spending more time at the foundation’s offices, staking a claim for herself. She became its voice on family planning, maternal care and other development-related issues that specifically affected women.

French Gates’ departure is the latest step in the evolution of the Gates Foundation, the world’s largest private foundation. From public health and development to agriculture and education, the foundation is a highly influential player, giving away billions of dollars annually.

Its future direction was thrown into doubt momentarily when Gates and French Gates announced their plans to divorce in May 2021, after 27 years of marriage. At the time, the foundation said that she would continue working with Gates as a co-chair, and that if either of them decided they couldn’t work together, French Gates would step down in May 2023 or later.

French Gates considered her working relationship with her ex-husband to be challenging, according to a person with knowledge of her thinking. After her divorce, French Gates said publicly that she and Gates maintained a friendly relationship, but that they weren’t friends.

In “The Moment of Lift,” her first book, published in 2019, French Gates wrote about how difficult it was at times to stand out alongside her husband. “I’ve been trying to find my voice as I’ve been speaking next to Bill,” she wrote, “and that can make it hard to be heard.”

After the couple’s 2021 divorce, the foundation introduced several changes as it sought to introduce stronger corporate governance mechanisms and professionalize its operations. Despite the foundation’s size — an endowment of $75 billion as of 2023, around 2,000 employees and roughly a dozen offices around the globe — it had long remained a tightly controlled entity where French Gates and Gates, the two co-chairs and co-trustees, oversaw much of the decision making, according to former employees and those who have worked with the foundation.

In 2021, soon after the divorce, Warren Buffett, who had joined the foundation as its third trustee after announcing in 2006 that he would give to it a majority of his fortune, stepped down from his role, saying that his participation was not needed, but that he would continue to make contributions. The next year, the foundation added six trustees to its board.

This article originally appeared in The New York Times.