Stock exchanges intend to fire the contractor they hired to build a data warehouse for all US stock-market activity, the latest sign of trouble for a project designed to detect trading fraud and causes behind wild swings in prices.

People familiar with the matter said the exchanges have lost confidence in Thesys Technologies, a startup hired in 2017 to build the repository, known as the Consolidated Audit Trail. The Securities and Exchange Commission told the exchanges to create the database so it would have a complete picture of orders in the stock and options markets, a tool they have never had.