Going back to 1950, there have been 13 instances where the S&P went at least 252 trading days without making a new high. However, once the index has been able to gather the steam to breakout to the upside, the forward looking returns have been rather encouraging. We looked at 1, 3, 6 and 12-month returns and the average, median and max performance are all very strong and can be seen in the table below.
S&P 500 Performance: When Index Goes At Least 252 Trading Days Without New High
We then took the study a step further in an effort to account for the environments in which these moves occurred. By our count, 9 of the 13 episodes happened in the midst of secular bull markets. As you can see in the stats above, the average returns for those periods alone are even more powerful with forward 12-month returns sitting at nearly 18%.
In the 4 occasions where the index took at least 252 trading days to make a new high while in a secular bear market (end dates: 1972, 1980, 2007, 2013), the average performance, while still positive, was much weaker than the total sample size. Forward 12-month returns averaged just 3.28%. Also note the huge divergence in time taken to make a new high between secular bulls vs bears.
We've shared some charts of the secular bull/bear periods for the S&P and Dow below for further reference: