the stock market crash of 1987

The Wall Street Journal has an interesting article today on the birth of the ETF–and the index fund, for that matter.

Two factors stand out to me as being missing from the account, however:

–when the S&P 500 peaked in August 1987, it was trading at 20x earnings.  This compared very unfavorably with the then 10% yield on the long Treasury bond.  A 10% Treasury yield would imply a PE multiple on the S&P of 10x–meaning either that bonds were dirt cheap or that the stock market was wildly overvalued vs. the bond market.

–a new product, called at the time portfolio insurance, a form of dynamic hedging, had very recently been created and sold to institutional investors by entrepreneurs steeped in academic efficient markets theory.  Roughly speaking, the “insurance” consisted in the intention to stabilize equity portfolio values by overlaying a program of buying and selling futures against the physical stock.  Buy futures as/if the market rises; sell futures as/if the market falls.

One of the key assumptions of the insurers was that willing/eager counterparties for their futures transactions could be found at all times and at theoretically predictable prices.  On the Friday before Black Monday–itself a down day–the insurers’ model required them to sell a large number of futures contracts.  Few buyers were available, though.  Those who were willing to transact were bidding far below the theoretical contract value.  Whoops.

On Monday morning, the insurers, who appear to have had negligible actual market experience, capitulated and began selling futures contracts at whatever price they could get.  This put downward pressure both on futures and on the physical market.  At the same time, pension funds, noting the large gap between the price of futures and the (much higher) price of the underlying stocks, began to buy futures.  But to counterbalance the added risk to their portfolios, they sold correspondingly large amounts of stocks.  A mess.

Arguably, we would shrug off at least part of this today as just being crazy hedge funds or algorithmic traders.  Back in 1987, however, equity portfolio managers had never before seen derivatives exerting such a powerful influence on the physical market.  It was VERY scary.

conclusions for today

Stocks and bonds are nowhere near as out of whack with one another as they were back in 1987.  The nearest we have today to a comparable issue is what happens as worldwide excess liquidity is drained by central banks from money markets.

The trigger for the Black Monday collapse came from an area that was little understood, even by those involved in it–activity that had severe negative unexpected consequences.  The investors who did the best after the crash, I think, were those who understood the most quickly what had happened.

Collateral damage:  one of the most important results of Black Monday, I think, was the loss of confidence in traditional investment advisers working for the big brokerage houses that it created.  This was, I think, partly because of individuals’ market losses, but partly, too, to the generally horrible executions received when they sold stocks in the aftermath.  This was the start of a significant acceleration of the shift to discount brokers and to mutual fund products.