The Financial Conduct Authority is mulling over creating a new set of rules for the largely unregulated currency markets after the completion of a raft of foreign exchange manipulation investigations.

FCA Chief Executive Martin Wheatley pledged to consider installing a new set of rules if the watchdog finds evidence of wrongdoing in relation to FX fixing allegations.

"If that evidence suggests a more fundamental problem, then you've always got a set of responses," said Wheatley.

"One response says you have to enforce against poor behaviour, and the other response is to look at the conditions that allowed that behaviour to exist. That is what we did with Libor and came up with a set of structural changes.

"Frankly it's an unregulated market and that would be a big policy change for global regulators to decide that FX needed to be a regulated market. The truth is we are at a very early stage and a long way off before we can make any conclusions."

The daily $5tn (£3.1tn, €3.7tn) currency market is the largest in the financial system and is pegged to the value of funds, derivatives and financial products.

Morningstar estimates that $3.6tn in funds, including pension and savings accounts, track global indexes.

Unlike stocks, futures or options, currency trading does not take place on a regulated exchange and is conducted in the over-the-counter derivatives market. All members trade with each other based on credit agreements and there is no arbitration panel to adjudicate disputes.

A number of banks around the world have revealed that they have launched internal reviews into their FX trading procedures, after America's Department of Justice and the Federal Bureau of Investigation launched a criminal investigation into whether the world's biggest banks attempted to manipulate the currency markets.

Switzerland's Financial Market Supervisory Authority (Finma) and FCA are also looking into whether FX market rigging has occurred.

According to reports, the FCA has now shifted its probe into a raft of currency traders' private accounts to see if they moved their own money ahead of client orders and before allegedly attempting to manipulate the FX market.