Waning stock volatility is pressuring the equity derivatives business, suppressing revenue and driving traders out of what was once a key Wall Street moneymaker, writes Gunjan Banerji for The Wall Street Journal.

Revenue in an equity derivatives business that focuses on listed options shrank by 41% in the US and by 28% globally during the first half of 2017 from the same period a year ago, according to data firm Coalition, which tracked 12 of the biggest banks in the world. The number of employees in equity derivatives at banks has contracted by about 10% since 2012, Coalition data also show.