Wealth of billionaires grew by $2T in 2024, report finds (theguardian.com)

Billionaires keep their massive wealth invested in assets rather than cash in their checking account. We had significant inflation in '24 and with that dollars got smaller. The resulting impact is that the billionaire who was worth $10B now had $12B as the valuations of their owned assets changed with inflation.

So "Billionaires kept pace with inflation in 2024" is probably a more accurate headline.

It comes out to a 15% increase, falling behind the stock market. What I really find interesting is that the previous year's growth was only a third of that, only beating the 3% CPI inflation by only a small margin, and possibly not beating real inflation.