Handicapping the market from here — what history tells us about the odds

Can history help handicap where markets head from here after the extraordinary path stocks have taken so far this year?

 The violence and velocity of the crash-and-surge moves in the major indexes has placed this market in rare company, with relatively few precedents to mine for hints of what has tended to come next.

Yet, predictably, the probabilities don’t line up in a single direction. So an investor trying to decipher the lessons of the past has to play a game of Always, Usually, Seldom and Never, classifying the evidence accordingly. 

The S&P 500 rebounded by nearly 20% in the second quarter, only the tenth calendar quarter since World War II when it gained more than 15%. Following the prior nine quarters, the index was always up the following three months, for an average of 9%, with the smallest advance an impressive 4%, according to Bespoke Investment Group.

In the ferocious bounce and follow-through rally off the climactic market low in late March, a series of rare “breadth thrust” readings were registered, measuring intense momentum and voracious demand for virtually every stock following the comprehensive liquidation through March.

One of these readings, tracked for years by Ned Davis Research, comes when at least 90% of all S&P 500 stocks surpass their 50-day moving average. This threshold was reached May 26. In the prior 19 times this has occurred since 1967, the S&P was always up over the following year, by an average of 17%.

Unanimity is rare when it comes to historical patterns, so these so-far foolproof setups have won plenty of attention and lend some weight to the “don’t fight the tape” bullish case.

Still, these analyses cover very narrowly defined conditions, and neither ten nor 19 instances from the past remotely approaches a statistically robust sample.

Then there’s the fact that they don’t quite fit with some circumstances that usually occur in situations like the one this market is in.

Let’s not forget that the power and persistence of the recent rally has come in part as a not-quite-equal reversal of similarly rare downside momentum and oversold conditions of the preceding collapse.

This whipsaw, on a net basis, left the S&P 500 down by about 4% year to date through six months. The index has been negative at the halfway mark 35% of all years since 1928. Over the second half of those years, the index usually delivers subpar returns. On average, according to Cornerstone Macro technical strategist Carter Worth, the second half of these years produced a 0.7% gain. Of the past six times the S&P was underwater at June 30 (2000, 2001, 2002, 2005, 2008 and 2010), it fell further four times, though the last instance in 2010 the S&P ran higher by 22% in the second half to salvage the year for…