Slowly but surely, Cameron and Tyler Winklevoss’ Bitcoin Trust is putting the final touches on its proposed cryptocurrency-backed exchange traded fund, filing for shares on the Nasdaq.

On Wednesday, the Bitcoin Trust filed with the Securities and Exchange Commission to sell 20.1 million shares on the Nasdaq exchange, reports Ciara Linnane for MarketWatch. The filing did not include a launch date or expense ratio, indicating the Bitcoin Trust is not close to coming to market.

In May, a regulatory filing revealed the Winkelvoss Bitcoin Trust will trade on the Nasdaq. In July, a Form S-1 filing with the Securities and Exchange Commission reveled the ETF, assuming it comes to life, would trade under the ticker “COIN.”

“The investment objective of the Trust is for the Shares to reflect the performance of the price of Bitcoins, as measured by Winkdex, less the expenses of the Trust’s operations,” according to the SEC filing. [Winklevoss Bitcoin ETF Still Moving Through Regulatory Process]

The brothers have also introduced the bitcoin index, or so-called Winkdex, which will also be used to price the value of assets held by the Winklevoss Bitcoin Trust. [New Bitcoin Index Due Out]

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.