A report published by Oxfam ahead of the start of the World Economic Forum in Davos on Monday said the world's roughly 3000 billionaires held a combined fortune of $US18.3 trillion ($A27.4 trillion) in 2025.
The anti-poverty and development organisation releases an annual report on global inequality ahead of the meeting in the Swiss alpine resort town of Davos.
Adjusted for inflation, the billionaires' wealth has increased by more than 80 per cent since March 2020. At the same time, nearly half of the global population continues to live in poverty, Oxfam said.
The report draws on data from multiple sources, including Forbes estimates of billionaire wealth, World Bank figures and the UBS Global Wealth Report.
Billionaire wealth grew by about 16 per cent last year - three times faster than the average rate of growth in previous years.
The world's 12 richest people now own more wealth than the poorest half of the global population, or more than four billion people.
The world's richest man, Elon Musk, earns in four seconds what an average person makes in a year, Oxfam said.
Musk would need to give away more than $US4,500 ($A6,738) every second for his fortune to begin shrinking.
Billionaires earn an average of $US6,000 ($A8,984) during a 20-minute power nap and $US145,000 ($A217,105) during an eight-hour night's sleep.
Some 65 world leaders are due to participate in this year's forum in Davos, Switzerland - a record number - along with dozens of central bank chiefs and finance ministers, plus titans of the business world.
Oxfam is one of the meeting's most steadfast critics, arguing the gathering of global elite too often pays only lip service to the problems of the poor.
Oxfam also warned that growing economic power among billionaires is increasingly translating into political influence, particularly in the United States, which it said is eroding democratic systems.
Forbes recently wrote that US President Donald Trump has "presided over the most lucrative presidency in American history", adding billions to his net worth, largely through cryptocurrency ventures.
Trump is leading the largest-ever US delegation to Davos and is scheduled to address the conference on Wednesday.
Oxfam's report said 100 billionaire families spent a record $US2.6 billion ($A3.9 billion) during the most recent US presidential election campaign.
The report also raised concerns about global media concentration, writing that "over half of the world's largest media companies have billionaire owners, and nine of the top 10 social media companies in the world are run by just six billionaires".
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