State Street has been tapped to help launch the first bitcoin exchange-traded fund (ETF).

In a new SEC filing, State Street is now listed as the administrator and transfer agent for the Winklevoss Bitcoin Trust, a proposed bitcoin ETF backed by investors Cameron and Tyler Winklevoss, the founders of the Gemini bitcoin exchange.

According to the filing, State Street would be responsible for the "day-to-day administration of the Trust" when it is launched, as well as maintaining its books of account and calculating the Trust’s net-asset value (NAV), or the value per share of the offering.

Also noteworthy are other changes that address questions that have come up during the filing's still ongoing comment period.

For example, the filing indicates the ETF would use a "purpose-built" system to verify that the associated custodians hold control of the private cryptographic keys that would allow them to transition ownership.

The new documentation touts this as a benefit of the Winklevoss filing in comparison to other efforts that have sprung up to launch alternative bitcoin ETFs.

"Other Digital Asset ETPs may not be able to or willing to provide 'proof of control' of the private keys that control their bitcoin," the filing reads.

While a step forward, the development comes amid a now years-long effort by the Winklevoss brothers to launch the ETF as a way to allow investors additional exposure to digital currency market movements.

The effort picked up momentum earlier this summer when the Winklevoss brothers filed to move their application to the BATS exchange, a decision that has set off what has become an extended period of public comment.

Despite the advancements, however, market observers believe it could be years before any of the multiple proposed bitcoin ETFs goes live.

Adding fuel to this speculation is the relative lack of education about digital currencies, as well as the continued issues faced by the bitcoin exchange sector, which remains plagued by breaches and security issues.

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