Also today, just as the rout was nearing its trough, we shared a story from the Wall Street Journal about a mystery trader who placed a $1 million bet that bitcoin will climb above $50,000 by December 28, 2018.

That trade was a call option purchased on the LedgerX platform, which received permission from the CFTC over the summer to launch the first swap execution facility for the clearing of bitcoin-linked derivatives, and began trading in the fall, before CME and CBOE launched their own bitcoin futures. As the WSJ detailed previously, if bitcoin is below $50,000 on Dec. 28, 2018, the options will expire worthless, and the $1 million will be lost. But if bitcoin rises above that level, the options give the owner the right to buy 275 bitcoins for $50,000 apiece—a transaction that would cost $13.8 million.

Some more details on the trade mechanics from Privateer's Aaron Brown:

... one or more people delivered 275 bitcoin (valued at $4.5 million at the time) to the LedgerX clearinghouse, and wrote one-year calls at a strike of $50,000 ($13.75 million in total) against them for a premium of $3,600 per coin ($990,000 total); that is, the buyer paid the seller $990,000 today, and has the right but not the obligation to buy 275 bitcoin for $13.75 million any time before December 28, 2018. These 275 bitcoin are held by the LedgerX clearinghouse and will be released on Dec. 28, 2018 to either the buyer (if the buyer exercises the option by paying $13.75 million) or the seller (if the buyer does not exercise).