Crypto exchange Gemini founders Tyler and Cameron Winklevoss have long sought the creation of a bitcoin exchange-traded fund.

And while that process remains in flux, a company tied to the brothers has won another U.S. patent related to the creation of exchange-traded products tied to cryptocurrencies and digital assets.

The patent was awarded to a firm called Winklevoss IP LLP, and both Winklevoss brothers are included as the inventors along with Evan Louis Greebel, Kathleen Hill Moriarty and Gregory Elias Xethalis.

The patent, awarded on June 19, details a method “for providing an exchange-traded product holding digital math-based assets” as well as the issuance of shares tied to that ETP. It adds to the body of intellectual property the Winklevosses have sought to obtain, though it’s not entirely clear when or how the concepts will be applied to real-world products.

An ETP, such as an exchange-traded fund (ETFs), is a type of security, the price of which is derived from other investment instruments – in this case, cryptocurrencies.

As CoinDesk previously reported, the Winklevoss brothers won a patent last month for a system that settles transactions for ETPs tied to cryptocurrencies. Like the other patent, this week’s award names a variety of cryptocurrencies, from major ones like bitcoin and monero to more obscure ones like BBQcoin.

Publicly available data shows that this week’s patent is the seventh crypto-related patent the Winklevoss brothers have received, with the first being awarded in December of last year.

The U.S. Securities and Exchange Commission (SEC) once denied a bid proposed by the Winklevoss brothers in March 2017 to list a bitcoin-tied exchange-traded fund (ETF), citing “the rules of a national securities exchange be designed to prevent fraudulent and manipulative acts and practices and to protect investors and the public interest.”

Winklevoss brothers image via Shutterstock