Both the Financial Services Authority (FSA) and Ofgem are involved following claims by somebody who worked for price-reporting company Icis Heren.
The Financial Services Authority confirmed the regulator had received “information in relation to the physical gas market and will be analysing this information”. At this juncture the investigation has not reached the stage of a full-blown inquiry under its statutory powers.
In a statement the energy regulator said: “Ofgem can confirm that it has received information relating to trading in the gas market and is looking into the issue.
“In preparing for full implementation of new EU legislation to tackle market abuse (REMIT), we will consider carefully any evidence of market abuse that is brought to our attention as well as scope for action under all our other powers.
“Ofgem has already activated its established procedures to review the information we have received.”
Icis Heren has supplied Ofgem with what it believes was evidence of suspect trading on 28 September, the date which marked the end of the last “gas year”.
The Guardian named its source as Seth Freedman, a former trader who worked for Icis Heren for nine months.
Energy secretary Ed Davey said he was “extremely concerned by the allegations and will be keeping in close touch with the regulators while they get to the bottom of this”.