Bill Gates, co-founder and former CEO of Microsoft, said in a tweet on Monday that he and his wife, Melinda Gates, will be splitting up after 27 years. The two will keep working together on philanthropic work, which has addressed education, gender equality and health care.

“After a great deal of thought and a lot of work on our relationship, we have made the decision to end our marriage,” Bill and Melinda Gates wrote in a statement that Bill Gates tweeted out.

“Over the last 27 years, we have raised three incredible children and built a foundation that works all over the world to enable all people to lead healthy, productive lives. We continue to share a belief in that mission and will continue our work together at the foundation, but we no longer believe we can grow together as a couple in this next phase of our lives. We ask for space and privacy for our family as we begin to navigate this new life.”

The decision reflects a personal change at the top of American business.

Bill Gates led Microsoft as CEO from its founding with Paul Allen in 1975 until 2000, leaving Steve Ballmer to run the company, while Bill Gates became chairman and chief software architect. In 2008 Gates left his day-to-day role at Microsoft to spend more time on the foundation.

Last year Bill Gates stepped down from Microsoft’s board as the coronavirus became a force around the world. He began spending more time on the nonprofit Bill and Melinda Gates Foundation alongside Melinda Gates. The two are co-chairs and trustees of the foundation, which launched in 2000.

Bill and Melinda Gates both worked at Microsoft. She had been a marketing manager at the software company. The two met at a dinner for Microsoft employees in 1987. “It took him quite a few months before he asked me out,” Melinda Gates later said. Bill Gates had weighed the pros and cons on a blackboard, and in 1994 the couple were married in Hawaii.

Financial details of the Gateses parting ways are not yet clear. Bill Gates owns 1.37% of Microsoft’s outstanding shares, which are worth more than $26 billion, according to FactSet. The couple were creators, along with Warren Buffett, of the Giving Pledge, which involves giving away more than half of their wealth.

At one point the couple decided to move $20 billion worth of Microsoft stock to the foundation as they sought to increase their commitment to philanthropy, Bill Gates wrote in a 2019 blog post. Today the foundation has over $51 billion in assets, according to a tax filing.

“In the case of Melinda, it is a truly equal partner,” Bill Gates said in the 2019 Netflix documentary “Inside Bill’s Brain.” “She’s a lot like me in that she is optimistic and she is interested in science. She is better with people than I am. She’s a tiny bit less hardcore about knowing, you know, immunology, than I am.”

Bill Gates is the world’s fourth richest person, behind Bezos, LVMH’s Bernard Arnault and Tesla’s Elon Musk, according to Forbes.

The announcement comes two years after Jeff Bezos, CEO of Amazon, said he and his wife, MacKenzie, were getting divorced. Bill Gates and Jeff Bezos are among the world’s richest people, and Amazon and Microsoft compete in the cloud computing business. Amazon said earlier this year that Bezos would be stepping down from his post as CEO and that cloud chief Andy Jassy would replace him.