No dynamic could be more important in 2018 for investors than how the Federal Reserve manages what should be an accelerating economy.
The question essentially becomes whether growth gets too strong. In that case, where GDP shows sustained gains above 3 percent and the Fed finally starts hitting its 2 percent inflation target, the central bank may go from tapping the brakes to slamming them.
That may be the only thing that can stand in the way of a market rally that has been impossible to stop.