TLDR
The Fast Money Index (FMI) is a daily gauge of how stretched the altcoin market has become. It rolls 7 measures of speculative excess, leverage, funding, positioning, momentum, into one number from 0 to 100. A low reading means the structure is calm. A high reading means leverage and speculation have crowded in and the market is fragile.
FMI is better used as gauge vs a forecast – it tells you the state of the market right now and where risk is building up the most, the kind of stress that’s easy to glance over when it’s spread across separate metrics.
It takes a market that’s hard to read and hands back a single number for how much risk has built up underneath the price. A follow-up piece covers the trade ideas built on top of it via a long/short pair trade that uses the gauge to time the setup.
Why I built it
This came out of a pattern I kept watching repeat.
In crypto, when a lot of money gets made fast and the underlying conditions don’t support the move, the market tends to roll over not long after. The gains are real on the way up, but they’re borrowed. The speculative capital that drove them is the same capital that leaves first when the mood turns and it leaves fast.
October 2025 was the cleanest example in recent memory.
ASTER launched in September and ripped higher inside the BNB memecoin frenzy, with traders piling into leveraged positions chasing quick profits across the BNB chain ecosystem. Within weeks the frenzy faded, capital rotated out of the riskiest tokens, and on October 10 the whole structure gave way in a single day. Over $19B in leveraged positions were liquidated and the memecoin sector lost roughly 40% of its market value, falling f
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