Question: Who was the chief executive of the New York Stock Exchange during Black Monday, which was when stock markets around the world crashed?
Sentence (from "John J. Phelan Jr."): John Joseph Phelan Jr. (May 7, 1931 – August 4, 2012) was an American financier who served as president and later chairman and chief executive of the New York Stock Exchange, where he introduced computerized trading technology.
Relevant evidence: Yes