MacKenzie Scott, the ex-wife of Amazon founder Jeff Bezos, has donated more than $4bn (£3bn) to food banks and emergency relief funds in four months.
In a blog post, Ms Scott said she wanted to help Americans who were struggling because of the pandemic.
Ms Scott is the world’s 18th-richest person, having seen her wealth climb $23.6bn this year to $60.7bn.
Much of her fortune comes from her divorce from Mr Bezos who is the world’s richest man.
“This pandemic has been a wrecking ball in the lives of Americans already struggling,” she wrote in a blog post on Tuesday, adding that she had picked more than 380 charities to donate to having considered almost 6,500 organisations.
“Economic losses and health outcomes alike have been worse for women, for people of colour and for people living in poverty. Meanwhile, it has substantially increased the wealth of billionaires.”
Ms Scott donated $1.7bn to 116 charities in July saying she wanted to call attention to “organisations and leaders driving change.” This takes her total donations for the year to almost $6bn.
Donations were focused on those “operating in communities facing high projected food insecurity, high measures of racial inequity, high local poverty rates, and low access to philanthropic capital.”
Last year she signed the Giving Pledge, promising to give away the majority of her fortune. The Giving Pledge is a commitment by the world’s wealthiest individuals and families to dedicate the majority of their wealth to giving back.
“I have a disproportionate amount of money to share,” she wrote in her pledge.
Charity experts have applauded the amount she has given away and how she has done it. Ms Scott has worked with a team of advisers to research thousands of organisations.
“We leveraged this collective knowledge base in a collaboration that included hundreds of emails and phone interviews, and thousands of pages of data analysis on community needs, programme outcomes, and each non-profit’s capacity to absorb and make effective use of funding,” she wrote.