According to JP Morgan and BofA, trading revenue is expected to fall by 15% in the final quarter

The catalyst mentioned here is low volatility "across the spectrum", despite the constant drumbeat of political and geopolitical events that would normally boost volatility.

WSJ reports that JPM and BofA executives mentioned the biggest falloff is from the area of fixed income, commodities, and currencies.

Trading revenue for the five largest banks with investment banking operations, as a group, fell 4.4% in the first three quarters of 2017 - compared to a similar period last year.

Well, if they can't find their dose of volatility, maybe they should start investing more in cryptocurrency trading desks.