I went back and looked the monthly bollinger bands on spx only a few occasions got to this width or higher-
Bollinger has said trends go to die in widening bands
55 bull market
74 bear market
1983 bull market
1998 very close to this level
2008 bear
could we say 2021
is an initiation like
1955 (post wwII/korean war)
1983 (post 70's inflation washout - 'death of equities')
or a buying climax after a lengthy run like 98-99