Raw transaction volume treats a coin that moved yesterday the same as one that sat untouched for five years. On-chain analysts know those are not the same event. Coin days destroyed and HODL waves are the tools that weight movement by age — and old coins moving is a louder signal than new coins churning.

Coin days destroyed

A coin accumulates one "coin day" for each day it sits unspent. Move it, and those accumulated coin days are destroyed. Coin days destroyed (CDD) sums this across the network, so it spikes when old, long-dormant coins move and stays quiet when only recently-active coins change hands.

Why care? Long-term holders are the most informed, most patient cohort. When they finally move size, it often signals a meaningful decision — taking profit into strength, or repositioning. A price rally on low CDD is new money churning; a rally on high CDD is old hands distributing into it. The second is more cautionary.

HODL waves

HODL waves visualize total supply banded by how long since each coin last moved — under a day, a week, months, years. Stacked over time, the bands show whether supply is maturing (coins aging into long-held bands, classic accumulation) or whether old supply is reawakening and being spent (bands of old coins shrinking).

Broadly: thickening long-held bands signal conviction and a tightening available float; old bands eroding during a rally signal long-term holders handing coins to newer buyers — late-cycle behaviour.

Reading them together

The combination is more powerful than either alone:

  1. Price up, CDD low, long-held bands stable — accumulation intact, move backed by patient holders.
  2. Price up, CDD high, old bands shrinking — distribution from long-term holders into strength. Caution.
  3. Price down, CDD low — weak hands selling, strong hands unmoved. Often nearer a bottom.

Caveats

Exchange and custody migrations can destroy coin days without real economic intent, so spikes need entity context before you read them as conviction selling. And these are regime gauges, not triggers — they describe who is acting, not precisely when price turns.

Takeaway

Coin days destroyed weights movement by how long coins sat still, flagging when old, informed holders act; HODL waves show supply by age, revealing accumulation or distribution. Read them together — high CDD and shrinking old bands into a rally is long-term holders distributing — and filter for custody moves before trusting a spike.