The Euphoria Debate: U.S. Stocks Vs. U.S. Real Estate

 | Jun 01, 2017 04:03PM ET

When an asset class (e.g., stocks, bonds, commodities, real estate, collectibles, etc.) skyrockets in price – when it surges higher without sufficient economic reason – a bubble develops. Technology stocks in the late 1990s. Housing in the mid-2000s. When the asset class inevitably nose-dives? The balloon implodes.

Speculative silliness has not been difficult for me to spot. In the late 1990s I warned stock investors not to get carried away by dot-com madness. A “New Economy?” More like a new catchphrase. As a financial blogger with a popular web site in the mid 2000s, I cautioned readers not to get caught up in property price insanity. Forty percent more to own than rent? Absurd.

Of course, identifying a bubble is not the same as quantifying one. If the identification is going to have meaning, there needs to be a way to measure the magnitude of a financial blister.

With respect to market-based securities, at least, Grantham Mayo Van Otterloo & Company (GMO) researched 40 bubbles and discovered that prices surpassed two standard deviations on each occasion. More telling, asset prices reverted back to long-term averages in every circumstance. Based on their research, the money management firm defined a bubble as a “two standard deviation” occurrence.

The problem with the two standard deviation story? A financial blob can get even larger before it bursts. Or it may act more like an unsightly cyst, biding time and waiting for something or someone to drain it.

Perhaps not surprisingly, GMO’s Jeremy Grantham has started to doubt his own understanding of stock market bubbles. In a recent interview with the Wall Street Journal, he described the current environment as “decently different” from other 2 sigma events. His reasoning? An absence of euphoria.

Granted, my dentist isn’t asking me about plopping a big chunk of his Rollover IRA dollars into Snapchat (SNAP). That said, investor equity allocation at 67.5% is near other speculative tops of 70% at a time when stock valuations are two standard deviations above the mean.