Bitcoin's (BTC) recent double-digit rally has sparked a positive sentiment shift among crypto options traders.

The leading cryptocurrency by market value has gained 13% this month, topping the $19,000 mark for the first time since Nov. 8, CoinDesk data show.

And consistent with the resilient rally, bitcoin options' "volatility smile" shows the demand for out-of-the-money (OTM) call options – bullish bets at strikes higher than the cryptocurrency's going market price – has increased relative to puts or bearish bets.

(By Omkar Godbole)