More info on exchange-traded Ethereum vehicle - trades in Europe but available to U.S. investors using Fidelity and possibly other brokers:
You can google “Ethereum XBT” or “COINETH”. Details can be found at
http://www.nasdaqomxnordic.com/etp/etn/etninfo?Instrument=SSE144580 (trading in Sweden in krona) and
http://www.nasdaqomxnordic.com/etp/etn/etninfo?Instrument=SSE144581 (trading in Stuttgart in euro)
https://xbtprovider.com/ provides NAVs. The ETNs trade very close to NAV, instead of the substantial premium that GBTC trades at in the U.S. vs. its underlying value in bitcoin. The availability of these to U.S. investors is another reason that GBTC's current 63% premium to NAV might come down.
At Fidelity, taxable accounts can execute online, the Fidelity symbols are ETHEREUM_XBT:SE (trading in Sweden in krona) and ETHEREUM_XBTE:SE (trading in Stuttgart in euro). For an IRA, the trade can only be placed with a human, not online, by calling their international desk at 800-544-2976, so the commission is higher than for online trades in a taxable account.
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ADDED Jan. 30:To trade any of these at Fidelity, make sure your account is enabled for international trading, then hover over "Accounts & Trade" until you get the dropdown > select "Trade" > "International" tab > then enter one of the Fidelity-specific symbols such as "ETHEREUM_XBT:SE". If you have any trouble or need to do the trade in an IRA, which requires a human, call their international desk is at 800-544-2976.