A €200bn-plus trade reported in error to one of Europe's largest exchanges this week has thrown up more evidence of the struggles firms are having in adapting to vast new trading rules.

Strict trade reporting requirements under the European Union's revised Markets in Financial Instruments Directive, which came into force on January 3, are designed to increase transparency in equities, fixed income and derivatives markets, enhance price discovery and make it easier for regulators to track who is trading what and where.