There's a chart altcoin traders check almost religiously: Bitcoin dominance. If you've wondered what it is and why people obsess over it, here's the plain-English version.
Bitcoin dominance measures Bitcoin's share of the entire crypto market's value. If the whole market is worth a certain amount and Bitcoin makes up, say, half of it, dominance is around 50%. Simple as that.
Why does it matter? Because it hints at where money is flowing. When dominance rises, capital is concentrating in Bitcoin — usually a sign of caution, with money seeking the safest corner of a risky market. When dominance falls, it often means money is rotating out of Bitcoin and into altcoins, chasing higher returns. That rotation is what people mean by "altseason."
So the classic pattern traders watch for goes like this: Bitcoin rallies first, dominance climbs, then as confidence builds, money starts spilling into alts, dominance drops, and altcoins have their run.
But — the usual caveat — it's a signal, not a crystal ball. Plenty of cycles have broken the pattern, and dominance can be distorted by stablecoins and shifting definitions of "the market."
Use it as one input, not gospel. It tells you the direction of the wind, not exactly when the storm hits.
Not financial advice. Do your own research.