Agustin Carstens: The BIS General Manager Who Called Crypto 'A Ponzi Scheme' — and Built CBDC Infrastructure

Agustin Carstens is the most publicly visible critic of private crypto among senior international financial officials. His statements — delivered with the careful weight of a Mexican central banker who has navigated peso crises, IMF programmes, and financial globalisation — have consistently challenged the intellectual foundations of the crypto project while simultaneously running the world’s most productive public institution for CBDC research.

This apparent contradiction is actually coherent, and understanding it is essential to understanding the BIS’s position in digital finance debates.

Career: Bank of Mexico and the Latin American Perspective

Carstens spent decades at the Bank of Mexico, rising to Deputy Governor and Finance Minister before becoming Governor — one of the most consequential Latin American central banking careers of his generation. His experience navigating Mexico’s financial volatility gave him a specific perspective on monetary stability: he had seen what happened when confidence in a currency collapsed, when capital fled, and when the monetary system failed to anchor economic expectations.

Before joining the BIS in 2017, he was a candidate for IMF Managing Director in 2011 — the contest that Christine Lagarde won — and served as Chair of the International Monetary and Financial Committee. His international experience gave him relationships with central bank governors and finance ministers across the world, making him effective as BIS General Manager in a role that is fundamentally about convening and influencing rather than commanding.

His Latin American background is relevant to his crypto views in ways that are not always acknowledged. Countries like Mexico, Argentina, and Venezuela have experienced the damage that monetary instability causes to ordinary citizens. Carstens’ skepticism of private crypto — assets that are inherently volatile and that exist outside any monetary authority’s stabilising influence — reflects first-hand knowledge of what monetary instability costs.

The Ponzi Scheme Quote and the Arguments Behind It

Carstens’ most famous statement on crypto — describing Bitcoin as a “combination of a bubble, a Ponzi scheme and an environmental disaster” — was delivered in 2018 and has been frequently cited since. It is easy to dismiss as hyperbole from a central banker defending institutional turf. The arguments behind it deserve more careful engagement.

The bubble characterisation draws on the price volatility of Bitcoin and other crypto assets, which at the time of the statement and repeatedly since had exhibited classic speculative bubble dynamics: rapid price appreciation driven by new buyer entry, disconnection of price from any cash-flow-based valuation, and rapid price collapse when sentiment shifts.

The Ponzi scheme characterisation is more provocative and more specific. Carstens’ argument — shared with a number of economists — is that Bitcoin’s value is sustained primarily by new investor entry rather than by any productive activity. Existing holders can exit only by finding new buyers willing to pay higher prices. Unlike a company, Bitcoin generates no earnings; unlike gold, it has no industrial utility at scale; its value is purely a collective agreement that proves durable only as long as new participants join.

The environmental disaster characterisation was most accurate at the time of the quote, before Ethereum’s switch to proof-of-stake significantly reduced the energy profile of the second-largest crypto network.

What Carstens does not claim is that blockchain technology is without value or that digital finance innovation is undesirable. His consistent position is that private crypto assets — speculative, volatile, outside monetary authority — are fundamentally unsuited to the monetary roles their proponents claim for them.

The BIS Innovation Hub: Building the Alternative

The BIS Innovation Hub, established in 2019 and expanded under Carstens’ leadership to centres in Singapore, Hong Kong, London, Paris, Frankfurt, Toronto, New York, and Stockholm, is the institutional expression of his alternative vision: central bank digital infrastructure rather than private crypto.

The Hub has been the most productive public institution in CBDC research globally, running experiments that private sector researchers could not conduct because they require cooperation among multiple central banks and access to central bank settlement systems.

Project mBridge demonstrated multi-CBDC settlement — allowing commercial banks from different countries to settle cross-border payments using their central bank’s CBDC without correspondent banking intermediaries. The project involved central banks from China, Hong Kong, Thailand, and the UAE, settling real cross-border transactions on a shared DLT platform. mBridge addressed a genuine problem — cross-border payments remain slow and expensive under correspondent banking — using central bank digital infrastructure rather than private crypto.

Project Guardian, run in collaboration with the Monetary Authority of Singapore, experimented with institutional DeFi — using tokenized assets and automated market makers in a regulated, permissioned environment. Guardian demonstrated that the efficiency benefits of DeFi protocols — automated settlement, programmable assets, real-time collateral management — could be realised without the regulatory gaps and consumer protection failures of permissionless DeFi.

Project Nexus developed interoperability standards for national fast-payment systems, allowing instant payments across jurisdictions through technical bridges rather than new infrastructure. This is less glamorous than multi-CBDC experimentation but potentially more immediately impactful — most countries already have domestic fast-payment systems, and connecting them is more achievable than building CBDC infrastructure from scratch.

The Hyun Song Shin Partnership

Carstens’ intellectual partnership with Hyun Song Shin — the BIS Economic Adviser and Head of Research since 2014 — has defined the BIS’s analytical contribution to digital finance debates. Shin is one of the world’s leading monetary economists, specialising in financial intermediation, capital flows, and monetary system architecture. His research on crypto — coauthored with BIS colleagues and published in the BIS Working Papers and Annual Economic Reports — provides the rigorous analytical foundation for the conclusions that Carstens communicates in public.

The partnership is unusually effective: Shin provides analytical depth that gives BIS positions academic credibility; Carstens provides institutional authority that gives BIS positions policy relevance. The BIS Annual Economic Report chapters on crypto and CBDC — among the most widely cited documents in international monetary policy — reflect this collaboration.

Their shared framework distinguishes between the technology layer (distributed ledger technology, smart contracts, tokenization) — which they regard as genuinely useful innovation — and the asset layer (private crypto assets) — which they regard as poorly designed monetary instruments. This distinction, which is not always made clearly in public debates, is essential to understanding why the BIS enthusiastically pursues CBDC and tokenized asset research while remaining deeply skeptical of Bitcoin and private stablecoins.

Influence on Central Banker Thinking

Carstens’ influence on how central bank governors think about crypto is substantial and probably underestimated. The BIS is the central bank of central banks — it provides banking services to its member central banks, hosts the Basel Committee and other standard-setting bodies, and convenes the global central banking community in Basel multiple times each year.

When the BIS publishes research, it reaches every significant central bank governor in the world through official channels. When Carstens speaks at BIS events — the Basel conferences that are among the most exclusive gatherings in international finance — his audience is the governors and senior officials who set monetary and financial policy globally. His consistent message — private crypto is a flawed monetary instrument, but central bank digital infrastructure is necessary and achievable — has shaped the intellectual framework within which central banks approach digital finance.

The result is a global central banking community that is significantly more skeptical of private crypto and significantly more engaged with CBDC development than it would have been without the BIS’s analytical leadership. That is Carstens’ most enduring legacy in digital finance, more lasting than any individual project or statement.