Eugene Fama won a Nobel Prize for his theory that markets are mostly efficient.

Robyn Greenwood and his colleagues titled their research paper "Bubbles for Fama" in response to Eugene Fama's skepticism.

The S&P 500 index has increased by almost 50% over the last two years.

The research paper "Bubbles for Fama" was published in 2019.

The "Bubbles for Fama" research identified four main indicators of a potential market bubble: high valuations, high volatility, high new stock issuance, and accelerating price increases.