Microsoft founder and philanthropist Bill Gates on Wednesday said Donald Trump Donald John TrumpObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE “hasn’t been known” for his charitable giving.

Gates took the jab at Trump during an interview alongside his wife, Melinda, at a panel discussion hosted by the news outlet ReCode.

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“He hasn’t been known for his philanthropy. He’s been known for other things,” Gates said to laughter, when asked if the presumptive GOP presidential nominee had been approached to sign a pledge to give away at least half of his wealth to philanthropic causes.

Gates has focused strongly on philanthropy since stepping down from his executive position at Microsoft years ago. He and his wife have paired up with Warren Buffett to push billionaires to sign “The Giving Pledge,” in which families commit to giving away more than half of their wealth to charity during their lifetimes or in their will.

More than 150 families have signed up for the pledge, including Facebook founder Mark Zuckerberg, Oracle founder Larry Ellison and the top executives at Airbnb and Salesforce.

Melinda Gates, with a smirk, said the couple has not approached Trump, adding that they are still working their way down Fortune’s list of billionaires.

“We don’t have any immediate plans to approach him,” she said. “I think we should probably let this cycle play itself out before we do anything related to that.”

Trump recently sent off $5.6 million in donations — including a $1 million check from his personal account — to veterans groups after he faced increasing questions about his pledge to donate funds raised during a January event that coincided with a GOP presidential debate he skipped.

Trump’s campaign says the candidate has donated more than $100 million to charity over the past several years. But he has so far declined to release his tax returns, which would shed more light on his giving.