Resistance is a price zone where selling pressure has historically outweighed buying pressure, causing price advances to stall or reverse. Prior highs act as resistance because traders who bought near the top are relieved to break even when price returns to that level, and short sellers who were positioned there before recognize the area as effective entry territory. Like support, the significance of a resistance level increases with the number of times it has been tested without breaking. When resistance is broken on strong volume, the principle of polarity suggests the old ceiling often becomes a new floor — traders who were short below that level are now under pressure and may buy back at the breakeven zone. The cleaner the resistance level (fewer consolidation bars within the zone), the more likely a decisive break changes behavior.
