
Supply Last Active 7y–10y totals the BTC whose unspent outputs were last moved seven to ten years ago. The measure isolates a three-year band of very old supply and is denominated in BTC.
An expanding band means seven-year entrants outweigh both spending and coins reaching ten years. It peaked near 2.42 million BTC on January 6, 2019, then declined as the 10y+ cohort began to form; this is why a shrinking age band does not by itself prove that dormant coins have returned to circulation.
Very old holdings may be deliberately stored or inaccessible, and age cannot tell which. The band also moves with the size of cohorts created years earlier. Compare its changes with 10y+ supply and old-coin spending before drawing conclusions about renewed activity.
If it remains unspent, it leaves the seven-to-ten-year band and joins 10y+ supply. Its age increases even though no transaction takes place.
Bitcoin began in 2009, so seven-year-old outputs could not exist before 2016. The early zero period is a consequence of the age requirement.
No. It measures observable dormancy, not access to private keys. Both long-term storage and lost coins can contribute to the same balance.