A bold bet on BlackRock's spot bitcoin BTC ETF (IBIT) crossed the tape Tuesday, suggesting expectations for a "moonshot" or rapid price surge in the world's largest publicly listed fund by month-end.

On Tuesday, a trader picked up 3,000 contracts of the IBIT $77 strike call option expiring on June 27, according to data source Barchart.com . The trader paid a total premium of $39,000 for the bullish exposure.

A call option gives the purchaser the right, but not the obligation, to buy the underlying asset at a predetermined price on or before a later date. A call buyer is implicitly bullish on the market.

The $77 strike call represents a bet that prices will cross that level before the expiry. In other words, the bitcoin-tracking ETF, which closed Tuesday at $60.40, is expected to rally by over 28% by June 27.

Pseudonymous observer EndGame Macro called it a high-conviction bet on a bullish breakout.

"With IBIT trading around $60.40 and the $77 strike sitting roughly 28% out of the money [above the spot price], this trader is either anticipating a major catalyst like a surge in ETF inflows, a macro pivot, or a regulatory greenlight or they’re hedging a much larger directional exposure," EndGame Macro said.

"Whether it’s a calculated moonshot or part of a broader positioning strategy, one thing’s clear: they’re expecting serious volatility before June 27," EndGame Macro added.

Bull mood returns

Overall, the mood in the IBIT options market shifted bullish on Tuesday, with the one-year put-call skew turning negative, according to data source Market Chameleon .

The negative shift indicates calls, offering asymmetric upside exposure, are again trading relatively costlier than puts,

The renewed bullish shift follows a brief period from last week when puts traded at a premium to calls, reflecting downside fears.