Energy regulator Ofgem on Tuesday unveiled new rules as part of its tougher stance on retail markets. Ofgem's tighter rules mean that energy suppliers are now banned from increasing prices on fixed-term tariffs in a bid to create a "simpler, clearer and fairer" energy market for customers. Building on reforms brought in earlier this year, energy firms will now also be banned from automatically rolling householders on to another fixed term offer when their current one ends. Andrew Wright, Ofgem's Chief Executive, said: "Ofgem is resetting the energy market in consumers' favour to make it simpler, clear and fairer. Today's extra protection for consumers on fixed prices is just one of a range of reforms we are bringing in over the next six months to hold energy companies to higher standards. If suppliers fail to deliver, then Ofgem stands ready to take enforcement action to protect consumers." He added that the watchdog's steps will "make it easier for consumers to 'vote with their feet' and for new suppliers to enter the market and take on the Big Six" - namely Centrica, SSE, EDF Energy, E.ON, Scottish Power and npower. While Centrica shares remained in positive territory as the announcement was made, SSE shares fell 1.58% to 1,429p. NR