Cameron and Tyler Winklevoss are planning to launch an index that tracks the price of crypto-currency bitcoin, bringing the twins’ idea of a bitcoin exchange traded fund closer to fruition.

The proposed bitcoin index, or so-called Winkdex, will also be used to price the value of assets held by the Winklevoss bitcoin Trust, a planned ETF that is currently going through SEC review, the Wall Street Journal reports. [Winkelvoss Bitcoin ETF Concept Inches Along]

“The creation of an index that better reflects accurate pricing is the next step in wider acceptance of bitcoin as an asset class,” Cameron Winklevoss, chief executive of MathBased Asset Index LLC, said in the article.

The trust’s sponsor is Math-Based Asset Services LLC, which was formed in mid-2013. The company will run the new benchmark, tracking bitcoin prices based on “qualified bitcoin exchange transaction data… over a trailing two-hour period,” according to the SEC filing.

Bitcoin is a type of decentralized digital currency based on a peer-to-peer network and can be exchanged through computers internationally without a financial intermediary. The system was first introduced by developer Satoshi Nakamoto in 2009.

The crypto-currency hit a record high of $1,242 per coin on Nov. 29, 2013, but the currency has plunged due to pricing and technology issues. Mt Gox, a bitcoin exchange, has halted withdrawals since the start of February.

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