Cameron and Tyler Winklevoss, the co-founders of Gemini bitcoin exchange, have chosen State Street as the administrator and transfer agent for the Winklevoss Bitcoin Trust, their proposed bitcoin exchange-traded fund (ETF).

According to a new SEC filing: “Digital Asset Services, LLC, formerly Math-Based Asset Services, LLC, is the sponsor of the Trust (the “Sponsor”); Delaware Trust Company is the trustee of the Trust (the “Trustee”); State Street Bank and Trust Company (“State Street”) is both the administrator (the “Administrator”) and transfer agent (the “Transfer Agent) of the Trust; and Gemini Trust Company, LLC, an affiliate of the Sponsor, is the custodian of the Trust (the “Custodian”).”

In its capacity as the Trust’s administrator, State Street will be responsible for the day-to-day administration of the Trust which includes maintaining the books of account; calculating the NAV; transmitting the NAV per Share to the transfer agent, the sponsor, Bats, and other entities as directed by the sponsor; and preparing financial information. As the Trust’s transfer agent, State Street will provide its services with respect to the creation and redemption of ‘Baskets’ by authorized participants; the issuance and redemption of shares, the payment, if any, of distributions with respect to the shares; the recording of the issuance of the shares and the maintaining of certain records.

“The Trust is expected to issue and redeem Shares from time to time only in one or more whole blocks of 10,000 Shares (each block of 10,000 Shares is a “Basket”)”, the filing explains.

The filing also states that the ETF would use a "purpose-built" system to verify that the associated custodians hold control of the private keys, CoinDesk noted.

“The Custodian’s Cold Storage System was purpose-built to demonstrate “proof of control” of the private keys associated with its public Bitcoin addresses. The Sponsor and the Custodian have engaged an independent audit firm to verify that the Custodian can demonstrate “proof of control” of the private keys that control the Trust’s bitcoin (“Proof of Control Audit”) on a monthly basis”, the filing reads.