An atomic settlement is the instant and simultaneous completion of a series of transactions. Often used in the context of cross-currency payments or transfers of assets such as securities, a key feature of an atomic settlement is that no transaction in the series can be completed unless all are completed at the same time. In other words, either all transactions occur or none occurs. The purpose of making transaction settlement “atomic” is to prevent different transactions from interfering with one another.
The ability to use atomic settlements is one of the key potential benefits to using distributed ledger technology to execute transactions with costs and in time periods that are significantly lower and shorter than currently required. As one example, the New York Federal Reserve’s “Project Cedar” tested the viability of atomic settlements of cross-border payments in illiquid currency corridors. In those tests, the settlement time for these payments was reduced from two days to ten seconds. The New York Fed’s full Report on Project Cedar is available here (https://www.newyorkfed.org/aboutthefed/nyic/project-cedar).