Financial markets are taking in a collective breath ahead of Jerome Powell's eighth and final keynote Jackson Hole speech as Federal Reserve Chair. If the moves following his last seven are any guide,

The president's latest attack comes as Powell is scheduled to deliver remarks at the Fed's annual conference in Jackson Hole, WY, on Friday.

Powell has never responded directly to Trump's provocations, and I, personally, expect this issue to play a predominant role at his latest meeting in Jackson Hole, perhaps even more so than the interest rate discussion. The independence of central banks is much more important than a 25 basis point change in the coming month.