You’ve probably heard: it’s the longest bull market ever. You’ve probably also heard: no it isn’t. What’s the story?
According to a loose consensus, bull markets are rallies that go beyond 20 percent and are never interrupted by a 20 percent fall. In many corners of Wall Street, that means the S&P 500 rally that began in March 2009 will surpass all that went before it on Wednesday.
Here’s the issue: the definitions aren’t chiseled in stone. They’re not laws of nature — it’s not even totally clear where they come from. The 20 percent threshold strikes people as arbitrary, spurious, an invention. Pundits disagree on everything from the role of psychology in defining market eras to how strict you should be about the parameters for past ones.
Several objections pertain to measurement. One is how to date the rally this one supposedly supplants — the dot-com bubble. Traditionally, statisticians have placed the start of the tech rally in October 1990, the bottom of a slide in the S&P 500 that got very close to 20 percent but not all the way. If you refuse to call that 19.92 percent drop a 20 percent drop, the advance gets longer, and today’s would need a thousand more days to exceed it.
“If you round the data, you’re going to get a certain number of bull markets. If you don’t round, you’re going to get a different number,” Justin Walters, co-founder of Bespoke Investment Group LLC, said by phone. “If you want to do that, that’s fine, but it’s not using the standard 20 percent definition.”
When a tradition coalesces on Wall Street, it’s hard to dislodge. The best argument for considering 1990 a break in a bull run is probably that much of the old guard considers it so. Different researchers give different verdicts — sometimes at the same shop. For better or worse, those eight 100ths of a point have been glossed over by history, leaving the 1990s run to begin in 1990.
Another analytical point: Who cares? Equities have been in good shape for years — maybe leave it at that. The stock market isn’t a geometry project, skeptics note, it’s a tool for capital formation, something people depend on for retirement. What difference does it make if the chart hews to a pattern in which declines of 20.1 percent matter and 19.9 percent don’t?
“We like records, we like round numbers, it’s a concept we like to talk about and tweet about,” Charlie Bilello, director of research at Pension Partners LLC, said by phone. “But no one in his right mind would use this as an investment strategy.”
Another objection, one pertaining to the custom of dating bull markets from trough to peak, looked less relevant Tuesday after the S&P 500 jumped above its record close from January. The concern had been that as long as the index held below its all-time high, it was impossible to say for sure that the rally was intact. Should it hold above that level at the close, the point would become moot.
Here’s a rundown of other ways that people say 3,452 days without a 20 percent decline do not a bull market make.