Buffett's investment results in the decade before 1951 were no better than average.

Factual claim about Buffett's own investing record from about 1941 (when he started investing at age 11) until 1951. True: biographical records (The Snowball, Buffett's own letters or interviews) show his returns over that period were roughly average, meaning comparable to or not clearly above the market. Mostly true: the results were broadly average but with a minor exception, or the period is slightly different. Mixed: the evidence is split, for example average early on and clearly above average later in the decade. Mostly false: the evidence shows his results were somewhat above average, and his statement is modesty that overstates his underperformance. False: documented returns show his results were clearly well above average for the decade.

Set before the research began.

1. E1 Case Study: Buffett's 50% Edge Against the Dow in the 1950s GuruFocus.com · 23 November 2019 Own record

   “For the decade of the 50s my edge averaged about 50 percentage points per year.”

2. E2 Case Study: Buffett's 50% Edge Against the Dow in the 1950s GuruFocus.com · 23 November 2019 Own record

   “For the year of 1951, Buffett’s investment return was 75.8% versus 21.3% for the Dow.”

3. E3 How Warren Buffett Made His First $100,000 GuruFocus.com (Geoff Gannon article) · 26 March 2012

   “My best guess is that Buffett compounded his money at an annual rate no less than 50% a year and no more than 60% a year.”

4. E4 How Warren Buffett Made His First $100,000 GuruFocus.com (Geoff Gannon article) · 26 March 2012

   “Buffett told students he did make 50% a year on his own portfolio before starting his partnership.”

5. E5 Case Study: Buffett's 50% Edge Against the Dow in the 1950s GuruFocus.com (article by user 'Grahamites') · 23 November 2019

   “Starting that year I calculated my results every year compared to those of the Dow. For the decade of the 50s my edge averaged about 50 percentage points per year.”

6. E6 Case Study: Buffett's 50% Edge Against the Dow in the 1950s GuruFocus.com (article by user 'Grahamites') · 23 November 2019

   “For the year of 1951, Buffett’s investment return was 75.8% versus 21.3% for the Dow.”

7. E7 How Warren Buffett Made His First $100,000 GuruFocus.com (article by Geoff Gannon) · 26 March 2012

   “My best guess is that Buffett compounded his money at an annual rate no less than 50% a year and no more than 60% a year.”

8. E8 Berkshire – Past, Present and Future Berkshire Hathaway (Warren Buffett letter) Own record

   “Indeed, the many dozens of free puffs I obtained in the 1950s made that decade by far the best of my life for both relative and absolute investment performance.”

9. E9 Berkshire – Past, Present and Future Berkshire Hathaway (Warren Buffett letter) Own record

   “Most of my gains in those early years, though, came from investments in mediocre companies that traded at bargain prices.”

10. E10 Berkshire – Past, Present and Future Berkshire Hathaway (Warren Buffett letter) Own record

    “My cigar-butt strategy worked very well while I was managing small sums.”

11. E11 Dow Jones Annual Return Rankings DQYDJ

    “The longest positive streak is 10 years: 1947 through 1956.”

The claim is about Buffett's results from about 1941 to 1950, but none of the evidence gives his returns for that period. E2, E5, E6 and E8 cover 1951 and the 1950s, which come after the period in question. E3, E4 and E7 describe roughly 50% annual returns "before starting his partnership," but the quotes do not say which years that covers, so they cannot show that his 1941–1950 results were above average. E11 gives only the Dow's record and nothing on Buffett's own returns, so the evidence does not settle the claim.