The UK's Financial Conduct Authority said today it would investigate potential "conflicts of interest" in dark pools over the next year. But with the private trading venues already squarely in the spotlight, the UK financial watchdog appears to be acting after the horse has bolted.

The FCA said in its annual business plan Tuesday that it would conduct a "thematic review" into dark pools, designed to "increase our knowledge of the conflicts of interest that may be inherent and explore how firms are managing them".