A support breakdown occurs when the price of a stock falls below a significant support level where it previously found buying interest. Support represents a price zone where demand was strong enough to stop the price from falling, but when this level is broken with strong selling pressure, it indicates that sellers have taken control of the market. This breakdown often leads to further downside movement as traders who bought near the support may start exiting their positions, adding more selling pressure. After the breakdown, the same support level frequently turns into resistance if the price attempts to move back upward.