Their decision puts at stake one of the world’s greatest fortunes and one of world’s largest philanthropy operations. Bill and Melinda Gates said on Monday that they were divorcing after 27 years of marriage. “After a great deal of thought and a lot of work on our relationship, we have made the decision to end our marriage,” the two said in a statement posted on Twitter. “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.” At stake is one of the world’s greatest fortunes — currently valued at $145.8 billion, according to the Bloomberg Billionaires Index — and one of the largest philanthropy operations on the planet. The Bill & Melinda Gates Foundation has given away more than $50 billion, contributing to the fight against Covid-19, leading the charge on climate change and advocating for women’s rights. Microsoft Corp. co-founder Bill Gates , 65, is the world’s fourth-riche...