Monitoring Bear Market Risk

The recent surge in US stock market volatility has rattled nerves and inspired some analysts to announce that a new bear market has arrived. The warning has resonated a bit deeper in some circles with the sight of the S&P 500 falling below its 200-day moving average earlier this month. The bearish view can’t be ruled out entirely, of course, but the latest stumble in stock prices looks like a temporary bout of anxiety rather than a start of an extended decline. Why? A key factor for this outlook is the economic trend, which continues to provide a bullish tailwind. Not surprisingly, an econometric test for bear-market signals in US stocks continues to show minimal signs of danger.

Analyzing the stock market with what’s known as a Hidden Markov Model (HMM) currently shows that the threat of a new bear market remains low. (For some background on HMM as applied at CapitalSpectator.com, see the posts here and here). Crunching the numbers on the S&P 500  in R with the depmixS4 package indicates a limited potential for a regime shift from a bull to bear market, based on one-year returns through Oct. 24. In the first chart below, the probability is shown to be virtually nil that a bear market was underway as of this past Friday, based on the current HMM signal.

sp.bear.mkt.prob.2014-10-27

A similarly upbeat profile emerges when we analyze the numbers through a binary prism that looks for bull and bear states. The current regime state is bullish.

sp.bear.mkt.state.2014-10-27

The standard caveats apply, of course. As with any model, there are no guarantees that an HMM-based view of the market is flawless. But history suggests that looking at the market’s trend through a relatively objective, statistical lens offers an encouraging real-time record of spotting new bear markets, as I discussed here, for instance.

Even if you accept the latest analysis, don’t confuse today’s results as signals written in stone. When a bear-market environment does arrive—as it will at some point—the charts above will change quickly. The lesson, then, is to run the numbers regularly, and as part of a diversified regimen of monitoring risk across a wide spectrum of macro and market indicators.

As for the US stock market, the current profile continues to look relatively positive. That doesn’t mean that short-term volatility has been banished or that the market will soar in the weeks ahead. But for the moment, the case for assuming that equities have entered bear-market territory is premature.