Paul Hanly from Sydney Australia emailed me about the time frames in this monthly update on market valuation. He writes:

It seems that the cycle has been roughly 12 to 20 years (plus or minus 3 years), although there can be violent sub-cycles (e.g., 1930-1950) where the lowest low was actually 1932 rather than 1950. But the tops were in a downtrend.

Here's a new chart with the duration of those secular trends documented. The chart is based on the S&P Composite monthly averages of daily closes, so the time frames will vary slightly from the peaks and troughs on a daily chart. For example the 2000 daily closing high was on March 24th, but the monthly high (average of daily closes) occurred in August.

The accompanying table documents the secular annualized returns, with and without dividends — a topic I'll address in more detail later this week.

Note that there are two entries for the 2000 bear — the first with the March 2009 low and the second from the 2000 peak to the present. The question, of course, is whether the 2009 low was a secular bottom, in which case we're a full year into the new bull market. Or is the real bottom yet to come?

Even though our data covers a timeframe of nearly 140 years, there have been too few of these mega-cycles to make meaningful generalizations. Prior to the current bear, the shortest was the 14-year 1968-1982 bear. If last year was truly the bottom of the bear, it will take the record for brevity.