Showing posts with label Stock market returns. Show all posts
Showing posts with label Stock market returns. Show all posts

Sunday, October 22, 2017

22/10/17: Leverage risk and CAPE: Why Rob Shiller Might Be Wrong


Rob Shiller recently waxed lyrical about the fact that - by his own metrics - the markets are overpriced, yet no crash is coming because there is not enough 'leverage in the system' to propagate any shocks to systemic levels.

The indicator Shiller used to define overpricing is his own CAPE - Cyclically Adjusted PE Ratio - and the indicator does indeed flash red:


CAPE is defined by dividing the S&P 500 index by the 10-year moving average of index components' earnings. The long-run average of CAPE is 16, and the index currently sits above 31, making the current markets valuations trailing those of the dot.com bubble peak (using recent/modern comparatives).

So the markets are very expensive. But what Shiller says beyond this mechanical observation is very important. His view is that these levels of valuations are 'sustainable' in the medium term because there is very little leverage used by investors in funding these levels of stock prices. In the nutshell, this says that if there is any major correction in the markets, investors are unlikely to be hit by massive margin calls, triggering panic sell-offs. So any correction will be short-lived and will not trigger a systemic crisis.

All fine with the latter part of the argument, if we only look at the stock market brokerage accounts leverage, ignoring other forms of leverage.  And we can only do this at a peril.

Investor is a household. Even an institutional one, albeit with a stretch. When asset prices correct downward, income received by investors falls (dividends and capital gains are cut) and investor borrowing capacity falls as well (less wealth means lower borrowing capacity). But debt levels remain the same.  Worse, cost of funding debt rises: as banks and other financial intermediaries see their own assets base eroding, they raise the cost of borrowing to replace lost income and capital base with higher earnings from lending. Normally, the Central Banks can lower cost of borrowing in such instances to compensate for increased call on funds. But we are not in a normal world anymore.

Meanwhile, unlike in the dot.com bubble era, investors/households are leveraged not in the investment markets, but in consumption markets. Debt levels carried by investors today are higher than debt levels carried by investors in the dot.com and pre-2007 era. And these debts underwrite basics of consumption and investment: housing, cars, student loans etc (see https://www.bloomberg.com/view/articles/2017-10-18/don-t-rely-on-u-s-consumers-to-power-global-growth). Which means that in an event of any significant shock to the markets, investors' debt carry costs are likely to rise, just as their wealth is likely to fall. This might not trigger a market collapse, but it will push market recovery out.



An added leverage dimension ignored by Shiller is that of the corporates. During the crises, cash-rich and/or liquid corporates can compensate for falling asset prices by repurchasing stocks. But corporates are just now completing an almost decade-long binge in accumulating debt. If the cost of debt carry rises for them too, they will be the unlikely candidates to support re-leveraging necessary to correct for an adverse asset prices shock.

I would agree with Shiller that, given current conditions, timing the markets correction is going to be very hard, even as CAPE indicator continues to flash red. But I disagree with his view that only margin account leverage matters in propagating shocks to a systemic level.

Wednesday, February 12, 2014

12/2/2014: The Origins of Stock Market Fluctuations


An exceptionally ambitious paper on drivers of stock markets changes over long time horizon. A must-read for my students in MSc Finance and certainly going on syllabus next year. Big paper, big conclusions.


"The Origins of Stock Market Fluctuations" by Daniel L. Greenwald, Martin Lettau, and Sydney C. Ludvigson (NBER Working Paper No. 19818, January 2014, http://www.nber.org/papers/w19818).

"Three mutually uncorrelated economic shocks that we measure empirically explain 85% of the quarterly variation in real stock market wealth since 1952."

This is an unbelievably strong statement. Traditionally, little attention is given "to understanding the real (adjusted for inflation) level of the stock market, i.e., stock price variation, or the cumulation of returns over many decades. The profession spends a lot of time debating which risk factors drive expected excess returns, but little time investigating why real stock market wealth has evolved to its current level compared to 30 years ago. To understand the latter, it is necessary to probe beyond the role of stationary risk factors and short-run expected returns, to study the primitive economic shocks from which all stock market (and risk factor) fluctuations originate."

"Stock market wealth evolves over time in response to the cumulation of both transitory expected return and permanent cash flow shocks. The crucial unanswered questions are, what are the economic sources of these shocks? And what have been their relative roles in evolution of the stock market over time?"

The authors use "a model to show that they are the observable empirical counterparts to three latent primitive shocks: a total factor productivity shock, a risk aversion shock that is unrelated to aggregate consumption and labor income, and a factors share shock that shifts the rewards of production between workers and shareholders."

And the core conclusions are: "On a quarterly basis, risk aversion shocks explain roughly 75% of variation in the log difference of stock market wealth, but the near-permanent factors share shocks plays an increasingly important role as the time horizon extends. We find that more than 100% of the increase since 1980 in the deterministically detrended log real value of the stock market, or a rise of 65%, is attributable to the cumulative effects of the factors share shock, which persistently redistributed rewards away from workers and toward shareholders over this period."

This is a huge result. "Indeed, without these shocks, today's stock market would be about 10% lower than it was in 1980. By contrast, technological progress that rewards both workers and shareholders plays a smaller role in historical stock market fluctuations at all horizons."

And on the risk aversion shocks? Uncorrelated with consumption or its second moments, these shocks "largely explain the long-horizon predictability of excess stock market returns found in data."

"These findings are hard to reconcile with models in which time-varying risk premia arise from habits or stochastic consumption volatility."

Massively important paper.