Can blockchain-based atomic settlements improve traditional financial markets?

Atomic settlement involves the conditional exchange of two assets. We model securities settlement in permissionless and permissioned blockchains and apply it to traditional financial markets. We find that a permissionless blockchain is optimal for US equities and foreign exchange, and a permissioned blockchain is optimal for US corporate bonds and treasury bills, and the gold market. We estimate that transitioning to optimal blockchain settlement could potentially improve gains from trade in foreign exchange by $17 billion, Nasdaq by $12 billion, US corporate bonds by $6 billion, gold market by $4 billion, and US treasury bills by $420 million annually.