The current period. Today we are ~17% over the 200d pretty rare territory. You can see two prior periods the Sept 2nd peak and the Late Feb peak (both periods resulted in giveback.)
Below is the Feb'18 peak where we topped out at 13.8% over the 200d. This was followed by a correction and a period of consolidation that lasted quite some time.
2013-2014 Bull run saw several over extended periods. Each resulting in some correcting. This chart is a good example of the difficulty of going from point A to point B, several areas on there it would have been easy to think the run was over. Notice during the whole period there was no real challenge to the 200d, with pullbacks being less than 10%.
2011-2012 In Early 2011 the market was still running hard off the 09 spring low. These overbought conditions resulted in a prolonged consolidation and pretty ugly correction before moving higher.
This is the rally off the 09 lows, it's one of only 2 periods that was more extended than the current market, while those first two peaks noted weren't good buying opportunities in the short term the pullbacks were shallow, but ultimately the market again entered a period of consolidation that lasted months.
Again following a bear market a strong rally ran up the S&P to over 13% over it's 200d. Repeating theme...The market then consolidated for an extended period, while the 200d caught up.
This is the very end of a 20yr previous secular bull market. Both in 99 and 2000 the market would extended beyond 10% over it's 200d. Unlike many of the charts above notice that volatility increased and pullbacks were testing the 200d repeatedly.
1997 more typical to most of the charts, following an strong bull run the market found itself overextended and entered a period of consolidation that would last many months.
1995-1996 The secular bull market began in 1982 and by 1995 was rather long in the tooth and fears of exuberance abound. It was during this period that the last leg of that secular trend began in earnest. We see a market that is overextended and stays that way. Certainly some give back, but that give back is shallow.
Now past is not prologue, but studying how traders in the past behaved in different situations can give us insight into how traders might behave in the future. It tells us something about probabilistic outcomes and helps set our expectations. Are we at the end of the secular cycle? Are we beginning a new leg of that cycle? How will the market behave differently depending on which of those two things is true? We don't have to guess, the market is going to show its hand.
Most investors who are bullish right now feel this period is most analogous to 1995-1996 and 2009-2010. If it is, pullbacks should be shallow, the market should show pretty strong support at the 50d (blue line) and deeper corrections should rally sharply.