A different kind of market indicator -- time

As I recently noted on TraderFeed, my research blog, most market indicators identify the presence of a particular market condition. A different kind of indicator takes an expectable market event and counts how many days have elapsed since that event has last occurred. This makes time itself a market measure that can be applied to any trading instrument. For example, my TraderFeed analysis found that, the longer the time that elapses before we see a five-day price high in SPY, the more positive are the short-term S&P 500 Index returns. Conversely, when we finally make a five-day high, near-term returns are subnormal.

For this analysis, we'll take a different expectable market event: The number of stocks making 20-day new highs exceeding the number that are making 20-day new lows. This measures breadth of strength in the market, as I include all operating companies in the NYSE, NASDAQ, and AMEX in the calculation.

What we find is that, since March, 2003 (N = 821 trading days), when we've had 11 or more days without new 20-day highs outnumbering new 20-day lows (N = 50), the next five days in SPY average a gain of .56% (37 up, 13 down). That is meaningfully stronger than the average five-day gain of .25% (434 up, 337 down) for the remainder of the sample.

On the other hand, if 20-day new highs already outnumber new 20-day lows (N = 552), the next five days in SPY display a somewhat subnormal set of returns going forward. Specifically, the next five days in SPY average a gain of .18% (307 up, 245 down) vs. an average five-day gain of .44% (164 up, 105 down) when 20-day lows outnumber new highs.

This accords with my earlier finding: the longer it takes for a bullish event to occur, the more bullish the near-term market outlook. Once the bullish event does occur, returns tend to be subnormal going forward. It is in this way that the market confounds human nature, which tends to overweight recent events in making judgments. The tendency to become more bullish as bullish events occur and more bearish as bearish events accumulate almost ensures losing performance over time.

I will be following this up with further time-based studies on the research blog. A daily count of 20-day new highs and lows is available on the Trading Psychology Weblog.

Brett N. Steenbarger, Ph.D. is Associate Clinical Professor of Psychiatry and Behavioral Sciences at SUNY Upstate Medical University in Syracuse, NY and author of The Psychology of Trading (Wiley, 2003). As Director of Trader Development for Kingstree Trading, LLC in Chicago, he has mentored numerous professional traders and coordinated a training program for traders. An active trader of the stock indexes, Brett utilizes statistically-based pattern recognition for intraday trading. Brett does not offer commercial services to traders, but maintains an archive of articles and a trading blog at www.brettsteenbarger.com and a blog of market analytics at www.traderfeed.blogspot.com. His book, Enhancing Trader Performance, is due for publication this fall (Wiley).