DislikedArb models drive much of the correlation, when they do run in tangent, it's typically synchronous movement (no lag or lead time).
Lately we've been seeing the correlation fall apart. As the Dow was driven to new lows Wed, Thurs, & Fri, USD/JPY never broke its Wed lows and in fact rallied on Friday.Ignored
A divergence opportunity perhaps? These rapid moves are often followed by pullback too.
TrevA