Is There a Bubble in the Economy?

The S an p 500 is much cheaper to day relative to short term rates than it was 21 years ago. Risk compensation is skimpy, as seen in the premium valuations of favored companies and in historically narrow yield spreads on credit. High multiples are justified by today's low interest rates, but dependent on continued low rates. The temperature of the market is elevated, and there are signs of euphoria and risky behavior.