The flow of economic data in the U.S. is remarkably positive, and it has been joined by a flow of positive economic data around the world. This is an extremely rare situation, where most of the world is enjoying solid growth.
They also believe the Republican tax cut will stimulate the economy slightly in the short term (maybe a modest 0.3% next year), but like myself, they believe it will stimulate the economy at the wrong time and only create inflationary pressures in the long term. This will cause long-term interest rates to increase. PIMCO would encourage you to refinance your mortgage now.
In other words . . . investors should continue to enjoy the ride!