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- Berkshire Hathaway CEO and chairman Warren Buffett's net worth is an estimated $138 billion.
- He's the world's 9th-richest person, per Bloomberg, above Sergey Brin and the Walton siblings.
- Buffett is known for living modestly and being one of the world's most generous philanthropists.
Warren Buffett is having a good year — his fortune has ballooned by around $18 billion.