$BTC.D down $BTC up : ALTS run.

BTC.D down BTC up : ALTS run.

Bitcoin dominance has broken down from its major uptrend and is currently in a retest.

It's important to remember that dominance alone isn't an altseason indicator; the key is for dominance to decline alongside Bitcoin's rise.

When this scenario plays out, a healthy altcoin season, as seen in the past, will resume.

So why did Altseason start in 2017 when BTC was falling?

1. Capital Rotation from Bitcoin to Altcoins

When Bitcoin approached $20,000 at the end of 2017, investors fell into the mindset that "BTC has risen too much, altcoins are cheaper."
Those who realized their profits sold Bitcoin and moved to altcoins.
So money didn't leave the market — it just changed direction within it.
That's why altcoins soared even as BTC fell.

2. New investor influx and FOMO

New investors entering crypto at that time turned to coins like Ethereum, Ripple, IOTA, ADA, and NEO, saying "Bitcoin is expensive."
New money flowed directly into altcoins.
So even as Bitcoin fell, the total market value continued to grow.

3. The historic collapse of dominance

BTC dominance fell from 65% in December 2017 to 35% in January 2018.
This was the sharpest "altcoin rotation" in history.
In short, everyone was "dumping their BTC profits into altcoins."

4. The ICO boom

Thousands of new projects were issuing ERC-20 tokens.
Demand for Ethereum skyrocketed because everyone was participating in ICOs with ETH.
This accelerated the shift from BTC to ETH and ignited the altcoin bull run.

5. Liquidity staying in the market

The stablecoin ecosystem was not yet developed (USDT was limited).
So when investors wanted to take profits, they were fleeing to altcoins instead of cashing out to fiat.
This caused altcoins to shine.