False breaks around the zero line

MACD’s zero line attracts attention because textbooks treat a cross through zero as a regime shift. In practice, price and MACD can hover around that line while signal-line crosses fire in both directions.

What we observe

On several KOSPI names in mild trends, MACD pierces zero, retreats, and pierces again within a few sessions. Traders who treat the first pierce as a regime change often reverse themselves within days.

A practical filter

Require the MACD line to close beyond zero by a minimum distance you define in advance—or require a confirming swing break in price—before a zero-line story can upgrade a signal-line cross. The exact distance is personal; the requirement to write it down is not.

Classroom caution

We do not claim zero-line filters remove uncertainty. They remove unexamined enthusiasm. Bring your own borderline examples to an evening clinic if you want them debated live.