France, Singapore and Switzerland have begun jointly testing experimental digital currencies (CBDCs) in a first-of-its-kind cross-regional trial, Reuters reports.

The project, which will last about six months, will use so-called automated market makers (AMMs) to exchange "hypothetical" CBDCs across borders in Swiss francs, euros and Singapore dollars.

AMM protocols are designed to combine pooled liquidity with algorithms to determine prices between two or more tokenized digital assets, such as currencies.

It is thought that they could become the backbone of the financial market infrastructure needed to trade digital currencies between countries.

About 90% of the world's central banks are either using, testing, or studying CBDC.