Why Banks Should Choose Public Blockchains Over Private Networks

Topics: blockchain · Difficulty: intermediar

Attila Kiraly — Strateg AI & Educator · · 3 min read

Reprezentare digitală a unei rețele globale conectând clădiri bancare moderne, simbolizând tranziția către blockchain public.

Originally published: September 19, 2026

The analysis explores why traditional financial institutions would benefit more from public networks like Ethereum rather than isolated, permissioned solutions.

What happened

A recent deep dive by a16z crypto challenged the prevailing trend of financial institutions building and utilizing "private" or "permissioned" blockchains. While banks were early adopters of Distributed Ledger Technology (DLT), most chose closed environments due to regulatory fears and a desire for control. However, current expert analysis suggests this approach severely hampers the technology's potential, essentially turning a blockchain into a slower, less efficient database without the benefits of global network effects.

Technology context

A public blockchain (like Ethereum) is a decentralized network where anyone can participate, verify transactions, or build applications without prior permission. In contrast, a private blockchain is controlled by a single entity or consortium, limiting access and visibility. The fundamental difference lies in composability—the ability of financial applications to interact with one another like Lego blocks. This is a native feature of public networks but is nearly impossible to achieve across isolated private systems.

Why it matters

For the finance industry, infrastructure choice dictates capital efficiency. Private blockchains create "data islands" that do not communicate, replicating the fragmentation of the current banking system (SWIFT, correspondent banking). By adopting public blockchains, banks can access global liquidity pools, reduce settlement times from days to seconds, and offer customers more transparent and accessible financial products. It marks a shift from proprietary silos to open standards.

Key terms explained

Impact

What's next

The central prediction is that the "Internet moment" for finance is approaching. Just as corporations eventually abandoned private Intranets in favor of the public Internet, banks will gradually migrate toward scaling solutions (Rollups) on public blockchains. These provide the necessary privacy via Zero-Knowledge technology while maintaining the connectivity of a global network.

Sources

Educational analysis generated with AI and editorially reviewed.

Original source: a16zcrypto.substack.com

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Frequently Asked Questions

Why do banks currently prefer private blockchains?

Banks opt for private networks primarily to maintain total control over data, comply with strict privacy regulations, and limit access to unauthorized participants.

What is composability and why does it matter?

Composability allows different financial apps to interact automatically. This enables developers to build complex services by combining existing protocols, much like Lego bricks.

Are public blockchains secure for sensitive banking data?

Yes, using technologies like Zero-Knowledge Proofs (ZKP), banks can verify transactions on a public network without exposing confidential client information to the public.

How does a public blockchain affect settlement times?

Traditional settlement often takes 2-3 days. On a public blockchain, transactions can reach finality in seconds or minutes, significantly reducing counterparty risk.

Will public blockchains replace SWIFT?

It may not replace it immediately, but it offers a more efficient alternative. Public blockchains provide a faster, cheaper rails for cross-border value transfer compared to legacy systems.

Glossary Terms

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