Golden Cross vs. Death Cross: What do they Signal?

A golden cross happens when a stock's 50-day average price rises above its 200-day average price, read as a sign the longer trend may be turning up. A death cross is the reverse: the 50-day average falls below the 200-day, read as the trend turning down.

Both are simply two moving averages interacting. The 50-day average summarizes roughly the last two and a half months of prices, while the 200-day summarizes roughly the last ten months. When the 50-day climbs above the 200-day, recent prices have been running above the longer history for a sustained stretch, and one good day cannot produce a cross, since it takes weeks of consistently higher prices to drag the faster average over the slower one. That is why people treat it as a trend signal rather than a news event. Two honest limitations: it is late by construction, and in a sideways market the averages cross back and forth producing signals that mean little. Part of its power is simply that millions watch it, which gives the signal some self-fulfilling weight.

A student's semester GPA rising above their overall college GPA. One good quiz can't do that, because it takes months of consistently better work to pull the recent average over the long-term one. A death cross is the mirror image: this semester dragging below everything that came before.