A condition in which price and cumulative delta move in opposite directions, signalling that the participants visible in the tape are not the ones driving the new extreme. In a bearish divergence, price prints a new high but cumulative delta fails to make a new high (or the bar's delta is negative) — buyers are not driving the high, so it is vulnerable. In a bullish divergence, price prints a new low but cumulative delta fails to make a new low (or the bar's delta is positive) — sellers are not driving the low, so it is vulnerable.