The proposal from a network of NGOs, social movements and pro-tax millionaires follows separate reports showing that the world’s wealthiest people have grown richer during the now two-year-old pandemic.

“The insane reality is that whilst billions face a daily struggle to survive during this pandemic, billionaire wealth is spiraling out of control. This cannot be right,” Jenny Ricks, global convenor of the Fight Inequality Alliance, said in a statement.

The tax proposal was made to coincide with a meeting of the World Economic Forum, which is taking place online for the second straight year as its Davos gathering was postponed due to the spread of the Omicron variant.

The report by the Fight Inequality Alliance, global charity Oxfam, the US-based Institute for Policy Studies, and Patriotic Millionaires, a group of high-net worth Americans, called for a graduated tax rate on the rich.

The wealth tax would be set at two percent for those worth over $5 million, three percent for over $50 million and five percent for over $1 billion.

This would raise $2.52 trillion, which could help pull 2.3 billion people out of poverty and produce vaccines for the entire planet.

It would also be enough to provide universal health care and social protection to 3.6 billion people in low- and middle-income countries, the group said.

The group said a steeper progressive tax, which includes a 10 percent levy on billionaires, would raise $3.62 trillion a year. It added that actual levels of taxation would be country specific.

Ricks told AFP the group chose a lower progressive tax that was on the “realistic side”.

Oxfam said earlier this week that the world’s 10 wealthiest men doubled their fortunes to $1.5 trillion during the first two years of the pandemic.

In an open letter to Davos participants, more than 100 millionaires — including members of Patriotic Millionaires — said the current tax system “is not fair”.

“The world — every country in it — must demand the rich pay their fair share,” the letter says. “Tax us, the rich, and tax us now.”