Major stock averages remain in earshot of all-time highs and this bull market has been nothing if not resilient, repeatedly defying predictions of its demise for five-plus years.
Still, Robert Shiller, Yale professor and Nobel prize winnner, is "definitely concerned" about the outlook for stocks based on the cyclically adjusted price-to-earnings ratio (CAPE) he created. At 26, the so-called Shiller PE is currently well above its long-term average of 17 and approaching levels that previously presaged doom for equities.
Shiller has plotted CAPE going back to 1881 and notes (with some alarm) it has only been higher than current levels three times: In 1929, 2000 and 2007.
"It looks to me like a peak," he says in the accompanying video. "I would think there are people thinking 'it's gone way up since 2009, it's likely to turn down again.' That's what people might plausibly think."
Anecdotal evidence does indeed suggest people are thinking "the end" of this bull run is nigh. But if the market "climbs a wall of worry," that's arguably a bullish sign as my colleague Michael Santoli describes here.
And Shiller is quick to note the CAPE is not a market-timing tool and he remains in the market in his personal account. "We don't know what it's going to do," he says. "Realistically, stocks should be in one's portfolio but maybe lighten up."
Stocks should be in one's portfolio in part because interest rates are so low and "the fixed income market just doesn't look very attractive," Shiller says.
As for the idea, proffered here by Citigroup's Tobias Levkovich, that CAPE is flawed because it doesn't "normalize" for interest rates (as it does for earnings), Shiller says the following: "He's right the very low interest rates are a sign maybe you want to keep more invested in the [stock] market now rather than getting nothing [from bonds]. That ought to help explain the high CAPE but that doesn't mean the high CAPE isn't a forecast of bad performance."
So what does Shiller, whose books include Animal Spirits and Irrational Exuberance, make of the recent steep declines in trading volume and volatility? Watch the accompanying video to find out.
Aaron Task is the host of The Daily Ticker and Editor-in-Chief of Yahoo Finance. You can follow him on Twitter at @aarontask or email him at email@example.com.
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