They just filed an S-1 with the SEC. They propose to create an ETF holding bitcoins, called the Winklevoss Bitcoin Trust.
This is nuts, of course. If you wanted to hold bitcoins, you could just buy them yourself. Why would you pay the Winklevii to hold onto some bitcoins for you? "Trust", indeed.
Felix Salmon says:
Still, if you want to own bitcoins, and you never want to spend your bitcoins, and if you want to pay the Winklevii for the privilege of looking after your bitcoins on your behalf, and if you trust that the Winklevii, after putting out a huge shingle saying “millions of dollars worth of bitcoins stored here”, won’t get hacked and lose all their coins, — then, well, then I’m afraid I have bad news for you. Which is that the SEC will never, ever, approve this product.The FT post linked from the S-1 image above also includes this animated GIF from The Social Network:
If you really want to do this, you could pay me! I'll hold your bitcoins for you. My fees will be lower than the Winklevii, and I'm much nicer than they are.