Approximately 176,000 $ZEC, worth around $81 million, were transferred to the new shielded Zcash Ironwood pool a day after the update activated and sealed the pool, where a vulnerability had gone unnoticed for 4 years.
This represents about 5% of the 3.66 million $ZEC held in Orchard at the time of activation. According to the Ironwood migration tracker, the Orchard balance has since fallen to approximately 3.51 million, with about 46,000 $ZEC passing through it in the last 24 hours.
Zcash stores funds in separate compartments called pools, each representing a generation of the network's privacy technology. The Transparent pool operates like Bitcoin: every balance and transaction is visible on the blockchain, and it holds about 12.5 million $ZEC.
Shielded pools conceal amounts and participants. The Sapling pool, introduced in 2018, contains about 582,000 $ZEC, while Orchard, which emerged in 2022 and was the newest until this week, held about 3.5 million. Each time the network updates its privacy cryptography, it opens a new pool rather than renovating the old one, leaving it up to holders to move their coins between them.
Orchard can no longer accept deposits. Every coin remaining inside must pass through a turnstile — an accounting rule that limits total withdrawals to the verifiably deposited amount, so the pool's balance can now only decrease.
The migration is voluntary, so the timeline depends on how quickly holders, wallets, and exchanges move funds. For now, the main supply of Zcash is in a pool that has been closed to new money since Tuesday.
