Carrick Mollenkamp and Charles Fleming:

As a result, banks are hiring an increasing number of recruits who understand derivatives. Inside banks, they are known as “quantitative analysts,” or “quants” for short. They are able to marry stochastic calculus — the study of the impact of random variation over time — with the realities of financial trading.
Derivatives are financial contracts, often exotic, whose values are derived from the performance of an underlying asset to which they are linked. Companies use them to help mitigate risk. For example, a company that stands to lose money on fixed-rate loans if rates rise can mitigate that risk by buying derivatives that increase in value as rates rise. Increasingly, investors are also using derivatives to make big bets on, say, the direction that interest rates will move. That carries the possibility of large returns, but also the possibility of large losses.
The 75 or so students who take Ms. El Karoui’s “Probability and Finance” course each year are avidly sought by recruiters. Three years ago, Joanna Cohen, a specialist in quant recruitment at Huxley Associates in London traveled to Paris to meet Ms. El Karoui to ensure her search firm was in the loop when students hit the job market. Today, Ms. Cohen says she carefully checks résumés with Ms. El Karoui’s name to make sure applicants aren’t overstating their interaction with the professor.