Key Takeaways
Bitcoin traders are paying increasingly high prices for upside exposure as the latest crypto rally spills into the options market for BlackRock’s largest spot Bitcoin ETF.
Call-option volume on the iShares Bitcoin Trust (IBIT) reached a record 1.58 million contracts on Aug. 19, according to Goldman Sachs data highlighted by The Kobeissi Letter.
The rush did not disappear after one session. Independent options data show roughly 1.3 million IBIT calls traded on both Aug. 20 and Aug. 21, keeping call volume above one million contracts for three consecutive trading days.
That is unusually aggressive activity for an ETF whose options market was trading only around 138,000 to 393,000 calls per day during much of the first half of August.
+7
Volume alone does not prove traders are betting outright on higher Bitcoin prices. Calls can also be used in hedges and multi-leg strategies.
The more revealing signal is call skew.
Goldman’s chart shows IBIT’s call skew rising 0.05 over three days, more than triple its average three-day move since January 2025 and the largest increase over that period.
Call skew tracks how expensive upside options are relative to downside protection. When it rises sharply, traders are paying a larger premium for exposure to gains.
In this case, the move accompanied a major Bitcoin rally. BTC crossed $70,000 after the US Treasury expanded planned long-duration bond buybacks and later reached a three-month high of about $79,455 on Aug. 21.
There is also cash entering the underlying ETFs.
US spot Bitcoin ETFs recorded $517.2 million, $606.3 million and $307.5 million of net inflows from Aug. 19 through Aug. 21.
IBIT alone accounted for approximately $1.03 billion across those three sessions, including $503 million on Aug. 20.
BlackRock reported IBIT net assets of about $60.34 billion as of Aug. 24, up from $46.96 billion on Aug. 14, although much of that increase also reflects Bitcoin’s price appreciation.
The combination is stronger than a call-volume spike in isolation: Bitcoin rallied, spot ETFs absorbed fresh capital and traders simultaneously paid more for upside optionality.
There is one caveat. Heavy call buying can magnify an advance if dealers hedge their exposure by buying IBIT shares, Bitcoin futures or related instruments as prices rise.
But the public data do not reveal enough about dealer positioning to conclude that this is already driving BTC higher.
For now, the clearest signal is simpler: after months of relatively restrained positioning, demand for leveraged Bitcoin upside has returned quickly, and at record scale in IBIT options.