WASHINGTON (AFP) - Food banks, immigrant rights groups, and struggling colleges across the United States discovered a surprise benefactor last year as billions of dollars flowed into organisations hurting during the pandemic.

Ms MacKenzie Scott, the ex-wife of Amazon founder Jeff Bezos, unlocked a staggering sum of nearly US$6 billion (S$8 billion) in charitable gifts last year, and, unlike many other large donors, did not attach any restrictions or even naming rights requirements.

The approach has shaken up the philanthropic world, not only with the size of her gifts, but without the limits and accounting requirements of many large foundations or donors.

Ms Laura MacDonald, board chairman of the Giving USA Foundation, a non-profit which conducts research on philanthropic giving, said Ms Scott's approach is part of a movement of "trust-based philanthropy" which does away with some of the red tape imposed by many donors.

Ms MacDonald said Ms Scott's approach moved beyond the "Big Brother" approach of some donors and the venture capital mindset which permeates much of the business world.

"Trust-based philanthropy has catapulted to the top of the list of taking points" in the philanthropic world as a result of Ms Scott's initiative, Ms MacDonald said. "This may embolden other donors to try something and take more risks."

In December, Ms Scott's latest funding round included 384 organisations ranging from Blackfeet Community College in Montana to the Arkansas Food Bank to the Immigrant Families Fund.

"This pandemic has been a wrecking ball in the lives of Americans already struggling," Ms Scott wrote in a blog post.

"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."

Philanthropy activists say Ms Scott's actions are likely to make other billionaires - including her ex-husband - take notice.

"There is a ton to celebrate about her philanthropy," said Mr Phil Buchanan, president of the Centre for Effective Philanthropy, which provides research data to foundations and other charitable donors.

"I would hope that the sheer amount of money she is getting out the door and her intention to continue to do so is a kick in the pants to all those sitting on tremendous wealth at time of unbelievable challenge and need."

Ms Scott, whose Amazon stake acquired in her divorce settlement is estimated at some US$58 billion, pledged to give away the majority of her wealth to fight social inequity.

She announced grants of some US$1.7 billion in July last year and another US$4.2 billion in December.

She enlisted a team of advisers to help identify organisations to help those suffering from the economic toll of the pandemic, focusing on those working to combat hunger, poverty and racial inequity.

While her ex-husband Mr Bezos has donated US$10 billion to fight climate change - the largest charitable gift of 2020 - and additional amounts to other causes, his giving has been slower and proportionately smaller, given that his fortune is worth more than three times hers.

The former couple could offer a major boost to philanthropy in the US, which represented some US$450 billion in donations from Americans in 2019.

Mr Benjamin Soskis, senior research associate at the Centre on Nonprofits and Philanthropy at the Urban Institute, said Ms Scott's actions are remarkable not only for their scale but the speed in delivering the funds.

"The pandemic has amplified an imperative in getting money out the door as fast as possible," Mr Soskis said.

Additionally, Mr Scott has broken with much of philanthropic tradition by eliminating onerous restrictions and limits, which can complicate matters for organisations scrambling to cope with the pandemic.

"She has emphasised giving money and getting out of the way," Mr Soskis said. "Philanthropists often see themselves as part of the process, with multiple checks and evaluations and metrics which can be really burdensome."

One potential critique of Ms Scott's approach is her "opaque" process in which she has selected grant recipients, Mr Soskis said.

"She is operating in a realm of absolute discretion that is not accountable to anyone," he said.

Still, Mr Soskis said her actions set an important precedent which could be a positive force for philanthropy.

"We shouldn't underestimate the role MacKenzie Scott plays in establishing a new norm for philanthropic giving," Mr Soskis said. "Any major philanthropist has to confront the example that she has set."