SPX closed below its BB band, touched the lower band of its weekly and monthly BB band in a retest of the year low.
While SPX was just shy of breaching the year low this past Friday, the Dow did.
For SPX to complete a large wave 4-down from its ATH, it likely needs to tread sideways to trace out a terminal triangle (blue).
A continued decline would complete a potential triple-three (leading expanding diagonal?) from the all-time high.