Nassim Taleb worked on Wall Street for close to two decades in trading and risk management of derivatives.

Judge against Taleb's documented career as of April 2008. True: his record shows about 17–21 years of derivatives trading or risk management in Wall Street / major financial-market institutions (e.g. roughly 1985–2005 at firms such as UBS, CSFB, BNP Paribas, Banque Indosuez, First Boston, DLJ and his own Empirica). 'Wall Street' may be read as the broader financial industry, including New York-based or international banks. Mostly true: the tenure is somewhat shorter (about 14–16 years), or part of it was outside Wall Street proper (e.g. Paris, London or Chicago trading pits). Mixed: the derivatives-trading career is real, but it lasted only around half of what is stated, or much of it was not trading or risk management. Mostly false: the career was substantially shorter (under about 10 years) or mostly in other roles. False: he did not have a derivatives trading or risk-management career in finance.

Set before the research began.

1. E1 My First Job: Professor and author Nassim Nicholas Taleb was a Wall Street trader The Independent · 13 March 2008

   “For 10 years, he operated as a "quant" and a trader.”

2. E2 Nassim Taleb - Biography MacTutor History of Mathematics Archive, University of St Andrews

   “Throughout this time he continued working as a derivatives trader but, after spending 21 years doing this”

3. E3 'Hottest thinker in the world' joins faculty NYU Polytechnic School of Engineering (NYU Engineering news) · 8 September 2008 Own record

   “Mr. Taleb spent twenty years as a derivatives trader and “quant” — a quantitative analyst who applies sophisticated math to risk management — before starting a full-time career as a scholar of risk and applied probability.”

The MacTutor biography from the University of St Andrews (E2), an independent source, says Taleb spent 21 years working as a derivatives trader. NYU's 2008 announcement (E3), which is not independent, gives twenty years as a derivatives trader and quant working in risk management. The Independent (E1) says he worked as a quant and trader for 10 years. That conflicts on the figure, but it may describe only one phase of his career. Most of the evidence points to roughly 20 years, which falls in the 17–21 year range the criteria set for "true".