A billionaire is a person whose total net worth, measured in US dollars, equals or exceeds one billion dollars ($1,000,000,000). As of 2026, there are approximately 2,800–3,000 billionaires worldwide, collectively controlling trillions in wealth.
The Forbes World's Billionaires List and Bloomberg Billionaires Index are the two most widely cited sources for billionaire rankings. Both use a combination of public stock filings, real estate records, and proprietary research to estimate net worths.
The threshold for billionaire status has grown increasingly meaningful as global wealth concentration has increased. The wealthiest billionaires — sometimes called "centi-billionaires" — have net worths exceeding $100 billion.