They are now likely to be lapped by Barry Silbert's SecondMarket.

The firm, whose Bitcoin Investment Trust (BIT) is already the largest regulated private Bitcoin investment fund in the world, has begun taking steps to open their own publicly traded, over-the-counter Bitcoin ETF, with a projected launch date of Q4 2014.

Because the BIT already complies with FINRA statutes, it will be able to file to open the exchange on a much more accelerated timeline than the Winklevosses, Silbert told BI Thursday.

"The plan all along was to move the [Bitcoin Investment Trust] into the public market in a similar way to the Winklevosses," he said. "But we've learned the route they're taking takes many years to get approved, and there's a high level of uncertainty when it will get done. [SecondMarket's process] does not require SEC approval."