$SanDisk Corp.(SNDK)$ Here is the reason for the chop — it was busy making a pattern. Yes, it has the structure of a bullish pennant or large symmetrical triangle, but with important caveats.

Pattern breakdown:

Flagpole: the explosive multi-month rally from near $0–250 up to the $2,250+ area is a classic, powerful flagpole.

Pennant / symmetrical triangle: after the peak, price has been coiling with a descending upper trendline (lower highs) and an ascending lower trendline (higher lows). The two lines are converging, which is the textbook shape of a pennant or symmetrical triangle.

Volume has generally contracted during the consolidation relative to the parabolic rise, which also fits the pattern.

On a monthly chart this is a large-scale version of the pattern, but the geometry is correct for a bullish continuation setup.