Percy Thomas
Real identity: Theodore Hazeltine Price, the "Cotton King" Pseudonym in Reminiscences: Percy Thomas
One of the most powerful cotton speculators of the early 20th century, Thomas appears in reminiscences-of-a-stock-operator as the man who "Thomasized" Jesse-Livermore — the only time in the book that Livermore's discipline was fully overridden by another person's persuasion.
Thomas's technique was patient and systematic: over weeks of conversation, he attacked Livermore's bearish cotton position with data, logic, and the accumulated weight of his expertise. He never argued emotionally. He simply kept building the factual case until Livermore's resistance eroded. The result was that Livermore covered his profitable short and went long at exactly the wrong time, losing heavily.
The lesson Livermore draws: even the most disciplined trader is vulnerable to a charismatic, data-equipped expert. The defense is the lone-hand philosophy — "If I fool myself, I alone suffer" — and recognizing the hidden third option between covering-and-going-long: simply going flat.