Zcash Security Fund Relies Heavily on Inherited Value After NU7

Zcash’s recently established reserve for future block rewards remains overwhelmingly composed of inherited value, according to mainnet data observed shortly after the network upgrade. The Network Sustainability Mechanism balance at block 3,547,068 was reported at 369.7 ZEC, with status data confirming that the NU7 upgrade was active.

Specifications governing the reserve set the historical seed at 368.58445520 ZEC. Subtracting this seed reveals that just 1.12 ZEC of subsequent accumulation has occurred under the rules introduced by the upgrade, accounting for roughly 0.3% of the observed total. The historical seed consists of transaction fees and subsidies left unclaimed in coinbase transactions before the prior NU6 upgrade.

Understanding Zcash Security and the NU7 Reserve

Under ZIP 237, this fixed amount is brought into the mechanism accounting to provide a positive starting balance before new fee contributions arrive. The upgrade registers transaction fees as the reserve's sole contribution mechanism. Specifically, 60% of each block's aggregate transaction fees are directed into the mechanism, rounded down to the nearest zatoshi, while miners receive the remainder.

Scheduled block subsidies remain separate from this fee allocation. The mechanism temporarily removes fee value from circulation and returns it through future block subsidies. However, the delay before payouts begin is substantial. Reserve reissuance is scheduled to start at block 8,939,664, meaning that elapsed time alone supplies no funding until that height is reached.

Zcash's new security reserve is 99.7% old money from unclaimed historical subsidies.

Before payouts commence, the fee-funded portion grows exclusively through cumulative fee spending. This initial observation cannot establish a sustainable annual funding rate, predict future usage, or determine whether eventual support will be sufficient for network security. Those questions depend entirely on ongoing fee demand over time and the balance available when gradual reissuance eventually begins.

Why it matters

This distribution highlights how transition periods in blockchain upgrades rely heavily on legacy funds rather than immediate network activity. For network participants and observers worldwide, understanding the exact composition of the reserve ensures clarity regarding how future security funding will evolve as fee demand develops over time.