Resolves YES if at any point before June 17 (UTC time), BTC is worth at least $1m USD according to https://coinmarketcap.com/currencies/bitcoin/. Otherwise NO.

If https://coinmarketcap.com/currencies/bitcoin/ is not available or up-to-date, another data source may be used.

Context:

(Note: this bet is a terrible bet in financial terms even if he thinks BTC will go up to $1m, because instead of taking this bet he could just buy $1m of BTC today and it would be worth 40x as much if he was right. Perhaps it's a good bet as a Twitter stunt though.)