The share of global wealth held by billionaires surged to a record during the COVID-19 crisis, according to a group founded by French economist Thomas Piketty.

About 2,750 billionaires control 3.5 percent of the world’s wealth, the Paris-based Global Inequality Lab said in a report Tuesday. That’s up from 1 percent in 1995, with the fastest gains coming since the pandemic hit, the group said. The poorest half of the planet’s population owns about 2 percent of its riches. The study’s findings add to a debate about worsening inequality during a public health crisis that’s hurt developing economies — which are short of vaccines as well as financial resources to cushion the blow — even more than advanced ones.