Checked · quotes
Five famous trading quotes, checked against the source and against our data
Lists of trading quotes are everywhere, and many of the lines in them were never said by the person named. We took a popular list, kept only what we could trace, and put each one next to a number we measured ourselves.
1. Templeton: "This time is different"
The source. Real, but usually reworded. In his 1993 "16 Rules for Investment Success", Sir John Templeton wrote that an investor who says it has "uttered among the four most costly words in the annals of investing". The popular "four most dangerous words" version is a later paraphrase. Source.
Our data. We let twelve AI trading agents play our replay game on real SOL candles: one run, then their own written lessons, then a second run on a different stretch. Ten of the twelve finished the first run in profit, on a falling market where shorting paid. Most wrote a rule like "trade with the tide". On the second stretch that rule lost, and none of the twelve finished in profit. One good run felt like a discovery. It was a market that happened to suit them.
2. Sperandeo: discipline, not intelligence
The source. Real. Victor Sperandeo told Jack Schwager in The New Market Wizards: "The key to trading success is emotional discipline." He added that if intelligence were the key, far more people would make money trading. Source.
Our data. In our game a player who passes on every single read finishes at exactly zero. The coin-flipping opponent we call the Ghost trades four reads in five and finishes below zero, because it pays fees: on the two stretches our agents played, its expected result was −0.5R and −3.6R. Doing nothing beat doing something at random, both times. Sitting out is a skill, and it is the one most players refuse to use.
3. "Buy when there is blood in the streets"
The source. An old market saying, not a verified quote. It is usually pinned on a Baron Rothschild, but the researchers at Quote Investigator trace it through decades of retellings of an anecdote, with different Rothschilds and even other financiers named. Treat it as a proverb. Source.
Our data. Buying the scary drop into a marked support level feels like exactly this kind of contrarian trade. We tested it: over 44 days of SOL, our graded zones held 46.0% of 315 taps. Random levels of the same size held 49.0% of 412. Being contrarian at a line on a chart was not an edge by itself. The full study is here.
4. Buffett: invest in yourself
The source. Real. Warren Buffett told Yahoo Finance in 2019: "By far the best investment you can make is in yourself." Source.
Our data. For a trader that means repetitions you can score. One run of our game is 15 reads, and its stats page refuses to give a verdict on your edge until you have at least 100 reads over 5 runs, because fewer than that says nothing. Practice counts when it is measured, and it costs nothing when the money is paper.
5. Bernstein: nobody knows the future
The source. The exact line that circulates, about a "fundamental law of investing", we could not trace. The idea is certainly his: in a 2004 interview with Jason Zweig, Peter Bernstein said that understanding we do not know the future is a simple statement and a very important one. Source.
Our data. This is why every figure we publish carries a range. Our zones held 46.0%, with a 95% range of 40.6 to 51.6%. Our top grade held 37.8% on only 37 taps, with a range of 24.1 to 53.9%, which is wide enough to mean very little. A number without its sample size is a guess.
The ones we left out
"The stock market is a crooked casino", as Charlie Munger. We found no source for that sentence. What he did say, at the 2022 Berkshire Hathaway meeting, is that stocks were being traded "on a casino basis". Source.
Four more lines from the same list, credited to Templeton, Buffett, Tony Robbins and Martin Schwartz, are left out because we have not traced them to a speech, book or interview. They may be genuine. We do not put words in a real person's mouth on a guess.
If a quote survives the source check, test it. That is what the tools here are for.