Ether, the Ethereum blockchain token, jumped 61% in the first six months of the year. Merchants are now betting the rally could have extended in the second half. On Friday, the investor bought roughly 63,250 “bull call spreads” tied to ether and expiring on December 29, according to data source Amberdata. The trade involved the sale of a call option at a strike price of $2,500 to partially finance the purchase of a call option at a price of $1,900. The strategy cost an initial $10 million because the trader entity spent more buying the $1,900 call than it received selling the $2,500 call. The buyer of the call gets protection from the price increase from the seller. In return, the seller receives an advance premium from the buyer.