Buffett will keep well over 99% of his net worth in Berkshire.

This is an ongoing commitment with no deadline, judged on all evidence from 2002 onward. True: Buffett's disclosed holdings (Berkshire proxy statements, Forms 4 and 13D, and Buffett's own statements) show that throughout the period, more than 99% of his net worth was in Berkshire stock. Shares he gave away do not count as a breach, because they are no longer part of his net worth. Mostly true: Berkshire stayed overwhelmingly dominant, but at some point the share was around 99% rather than clearly above it. Mostly false: he held a material non-Berkshire portfolio, roughly 1–5% of net worth, for a sustained period. False: evidence shows that a substantial share of his net worth (more than about 5%) was moved out of Berkshire into other assets that he kept, rather than given away.

Set before the research began.

1. E1 Buffett Posts Negative Outlook in Annual Letter Los Angeles Times · 11 March 2002

   “Buffett’s stake in Berkshire is worth about $34 billion, which he says is 99% of his net worth.”

2. E2 Warren Buffett Net Worth 2026: $145B (Forbes) | NetWort NetWort · 8 August 2026

   “Nearly all of it is Berkshire Hathaway stock. Buffett said it himself in a company release: Berkshire makes up "roughly 99 and a half percent" of his net worth”

3. E3 Buffett's Final $140 Billion Trade: Here's Where All His Stock Is Going, and Who Got Left Out 24/7 Wall St. · 15 July 2026

   “committed to giving away every remaining share he owns, currently worth more than $140 billion, to four family foundations by December 31, 2034.”

4. E4 Warren Buffett Net Worth 2026: $145B (Forbes) | NetWort NetWort · 8 August 2026

   “Warren Buffett's net worth was $145 billion, according to Forbes' "Top 10 Richest People In The World" list dated 1 August 2026”

E1 reports Buffett's roughly $34 billion Berkshire stake in 2002, which he said was 99% of his net worth. E2 quotes a company release, undated in the source, putting Berkshire at "roughly 99 and a half percent" of his net worth. E1's figure puts the share at about 99% [E1], while E2's figure of roughly 99.5% is above 99% [E2]. A rough comparison of E3 and E4 (over $140 billion in remaining shares against a $145 billion net worth) gives a lower share, but those figures come from different sources and dates and are approximate. Nothing in the evidence shows a material non-Berkshire portfolio, but the coverage is thin, so the claim is judged mostly true rather than true.