Company: BTC
Filing Date: 2025-04-01
Form Type: POS AM
Source: 0001193125-25-070549
Chunk: 159

Company: Grayscale Bitcoin Mini Trust ETF
Filing Date: 2025-04-01
Form: POS AM
Chunk 159
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 addition, the
Custodian has agreed to allow the Trust and the Sponsor to take any necessary steps to verify that satisfactory internal control system and procedures are in place, and to visit and inspect the systems on which the Custodian’s coins are held.

If the Custodian resigns in its capacity as custodian, the Sponsor may appoint an additional or replacement custodian and enter into a
custodian agreement on behalf of the Trust with such custodian. Furthermore, the Sponsor and the Trust may use Bitcoin custody services or similar services provided by entities other than Coinbase Custody Trust Company, LLC at any time without prior
notice to Coinbase Custody Trust Company, LLC.

Custody of the Trust’s Bitcoin

Digital assets and digital asset transactions are recorded and validated on blockchains, the public transaction ledgers of a digital asset
network. Each digital asset blockchain serves as a record of ownership for all of the units of such digital asset, even in the case of certain privacy-preserving digital assets, where the transactions themselves are not publicly viewable. All
digital assets recorded on a blockchain are associated with a public blockchain address, also referred to as a digital wallet. Digital assets held at a particular public blockchain address may be accessed and transferred using a corresponding
private key.

97

Key Generation

Public addresses and their corresponding private keys are generated by the Custodian in secret key generation ceremonies at secure locations
inside faraday cages, which are enclosures used to block electromagnetic fields and thus mitigate against attacks. The Custodian uses quantum random number generators to generate the public and private key pairs.

Once generated, private keys are encrypted, separated into “shards”, and then further encrypted. After the key generation ceremony,
all materials used to generate private keys, including computers, are destroyed. All key generation ceremonies are performed offline. No party other than the Custodian has access to the private key shards of the Trust, including the Trust itself.

Key Storage

Private key
shards are distributed geographically by the Prime Broker and the Custodian (together, the “Custodial Entities”) in secure vaults around the world, including in the United States. The locations of the secure vaults may change regularly and
are kept confidential by the Custodian and the Prime Broker for security purposes.

The Vault Balance primarily uses “cold”
storage mechanisms to secure a substantial portion of the Trust’s private keys. A substantial portion of the Trust’s Bitcoin holdings are held in cold storage at all times, with a portion of the Settlement Balance held temporarily