In it’s first day of trading in the regulated marketplace, Bitcoin traded at a record high (in USD) of $1,337.00 per BTC.  GBTC is an investment vehicle which represents approximately 1/10, or .1 BTC per share.  More information on the security can be found here.

Edit: More information is available here, on Reddit.

Edit 2: Some discussion in the Investing sub-Reddit.

Edit 3: From BitcoinTalk, a Bloomberg Terminal screenshot.