Bitcoin 21M Supply Cap Under Scrutiny After BlackRock ETF Explainer

• BlackRock’s Bitcoin explainer video includes a disclaimer about the potential for changing Bitcoin’s 21 million supply cap.
• Sebastian Perez criticizes the disclaimer for undermining Bitcoin’s core principles.
• Bitcoin developers Adam Back and Peter Todd clarify that altering the supply cap is highly unlikely and would require community consensus.

BlackRock released an explainer video about Bitcoin for its iShares BITI ETF offering, discussing why BTC matters, its evolution, limited supply, and global appeal. However, in the section addressing Bitcoin’s fixed supply, the video included a disclaimer stating that there is no guarantee Bitcoin’s 21 million supply cap will not be changed.

This disclaimer has raised eyebrows in the crypto community, with several members concerned that the message could undermine Bitcoin’s fundamental principles.

Sebastian Perez, CEO of Quiverflow Inc., criticized the disclaimer and pointed out the perceived silence from prominent Bitcoin developers like Adam Back and Peter Todd. Perez said Bitcoin’s decentralization and core principles need stronger defense, especially against corporate interests.

Adam Back Provides Clarity

Adam Back, a Bitcoin developer and CEO of Blockstream, responded to the controversy surrounding the BlackRock advertisement. After reviewing the ad, Back suggested that the disclaimer was likely a precautionary measure for legal reasons. 

He explained that BlackRock cannot guarantee Bitcoin’s fixed supply cap as a financial institution offering investment products since it is not under their control.

“Obviously their lawyers made them write that as they sell investment products, and they don’t have control,” he said.

In parallel, Back dismissed the idea of changing the supply cap, characterizing the disclaimer as a legal safeguard rather than a real threat to Bitcoin’s integrity.

Contributions from Other Bitcoin Core Developers

Meanwhile, early Bitcoin contributor Peter Todd acknowledged that while the supply cap could technically be altered if the community reached a consensus, this remains an extremely improbable scenario. Todd also referenced his past writings on the concept of tail emissions .

Charlie Shrem, founder of The Bitcoin Foundation, argued that Bitcoin’s 21 million supply cap is a core element of its design. He warned that any attempt to change the cap would effectively transform Bitcoin into a completely different cryptocurrency, framing the issue as one of technological architecture rather than politics.

In response to Shrem, Back reiterated that the disclaimer was a legal precaution. He reassured the community that Bitcoin’s decentralized nature makes such a change highly unlikely without universal consensus.
Javier Bastardo, marketing lead at stablecoin issuer Tether, argued that the disclaimer simply reflects the reality of the situation. While he agreed that altering Bitcoin’s supply cap is highly unlikely, he noted that it is still technically possible.