David Marcus on Lightspark: building a Bitcoin-native global payment network to replace correspondent banking

Summary

David Marcus, co-founder and CEO of Lightspark, is building what he describes as a Bitcoin-native replacement for correspondent banking, the network of bilateral agreements between banks that currently underpins most cross-border payments. The core thesis is that Bitcoin, as the most neutral and liquid digital asset ever created, is the only credible settlement layer for a truly open global money network, provided the infrastructure around it is fast and cheap enough to be practical.

From Libra's Failure to Lightspark's Foundation

Marcus ran PayPal for several years before joining Meta, where he led the Libra and Diem projects. Those efforts collapsed after Janet Yellen effectively shut them down on a single morning in June 2021. Marcus left Meta at the end of December 2021 and founded Lightspark in April 2022, carrying the core lesson from Libra: any interoperability layer for global money must be built on something sufficiently decentralized that no single government or regulator can unilaterally kill it. Bitcoin fit that criterion; a Facebook-sponsored stablecoin did not.

Two Products, One Network

Lightspark operates two distinct but complementary offerings. The first is Spark, a new Bitcoin L2 launched to address Lightning Network's core limitations around liquidity routing, channel complexity, and programmability. Spark is backward-compatible with Lightning but enables self-custody wallets, token issuance, stablecoin issuance, AMMs, and decentralized trading platforms on Bitcoin for the first time. Fees on Spark-based stablecoin transactions are paid in the stablecoin being transmitted, not in a separate gas token, which Marcus positions as a structural advantage over EVM-based chains like Ethereum. Users also retain a unilateral exit path to Bitcoin L1, preserving trustlessness even when transacting in stablecoins.

The second product is Universal Money Address (UMA), an open-source, pre-transaction messaging protocol that functions like email for cross-border payments. A user at Nubank, which has over 100 million bank customers in Latin America, would hold an address such as $name@nubank.com. A US sender initiates a dollar transfer; UMA queries the recipient institution for currency preference, exchange rate, and fees; the sender sees the exact amount the recipient will receive in Brazilian reais; and upon confirmation, the dollar converts to Bitcoin, moves over Lightning, and arrives in Brazil within roughly one second, converting to reais on arrival. The system operates 24/7, including weekends and bank holidays, at low cost. Institutions capable of handling their own Bitcoin conversion, like Nubank, connect directly. Others route through Lightspark's managed service.

Stablecoins: Global Use Case, Limited Domestic Application

Marcus draws a sharp distinction between where stablecoins create genuine value and where they are largely redundant. For users in Argentina, Venezuela, Turkey, and parts of Africa, dollar-denominated stablecoins, primarily Tether, serve as a practical substitute for US bank accounts that are otherwise inaccessible. For institutional capital markets, stablecoins solve real problems around weekend settlement and interbank liquidity. For the average American consumer, he sees no compelling use case; Venmo and Chase balances already function as virtualized dollars, which is effectively what a stablecoin is. Corporate-branded stablecoins he views with similar skepticism, comparing them to loyalty currencies.

He is equally direct on the limits of stablecoin decentralization. Circle can freeze all USDC. Every stablecoin is fully centralized at the issuer level, which is precisely why Marcus argues the network layer must not be centralized as well. Programmability via smart contracts, he notes, inherently trades away trustlessness, and those two properties will always be in tension.

Developer Adoption and the Bitcoin Renaissance

Marcus argues that developer energy flowed to Ethereum, Solana, and other L1s not because of ideological preference but because Bitcoin simply lacked the tooling to build on. Coinbase and several of the largest global exchanges now use Lightspark's infrastructure to move Bitcoin faster and cheaper over Lightning. With Spark now live, he expects a material shift of developer activity back to Bitcoin, citing permissionless builders deploying payment apps, stablecoin products, and trading platforms without any formal onboarding or contracts with Lightspark.

Regulatory Shift

Marcus, whose Diem project was among the most publicly visible casualties of the prior administration's crypto posture, describes the current environment as a dramatic reversal. He attended the digital asset summit at the White House and credits David Sacks and Bo Hines specifically, along with Congressional action on the GENIUS Act stablecoin legislation. He identifies the pending market structure bill as the single most important remaining legislative item for the industry in the second half of 2025, ranking it alongside the stablecoin legislation in significance.