A group of US stock exchanges is set to fire Thesys Technologies, the startup it hired in 2017 to build a vast Consolidated Audit Trail (CAT) tracking transactions as they pass through US equity and options markets, according to the Wall Street Journal.

Citing sources, the Journal says that the exchanges, collectively called the self-regulatory organisations, have lost confidence in Thesys and that the Financial Industry Regulatory Authority is expected to take over the project.

The CAT will create a single data warehouse to record and store the complete lifecycle of all orders and transactions passing through US trading venues.

The moves to build the database were sparked by the flash crash of 2010, which demonstrated the Securities and Exchange Commission's inability to keep pace with sub-second trading patterns initiated by automated robot traders.

Thesys won the bidding to build and manage the project, beating out competition from 30 rivals, including Finra and tech giants Google, IBM and SunGard.

But the firm was a year late in delivering the first stage of the project and has now been sidelined, although a Thesys spokeswoman tells the WSJ that the parting is mutual and due to "irreconcilable differences".