Billions of Bitcoins are either lost forever or haven't moved in over a decade

132,000 Bitcoins are stored across 4 dormant wallets
$9 billion in holdings
Zero activity
The largest holds 53,880 Bitcoins worth $3.7 billion
The last movement was 12 years ago
Another wallet contains 31,000 Bitcoins and has not sent any transactions since 2010
One of these wallets sent 40,000 Bitcoins once through a series of addresses to Jad Malab, founder of Mt. Gox
Mt. Gox later collapsed, losing 850,000 Bitcoins
It is believed that about 20% of the total Bitcoin supply is permanently lost
This is roughly equivalent to $250 billion in Bitcoin value
Quantum computing may someday be able to crack those keys
If that happens, dormant wallets could become the biggest targets in history