More than half a million customers switched to different electricity suppliers in September.
It was the highest number of switches in a month so far this year, at 547,660, according to latest figures from Energy UK.
That takes the total number of customers moving to different providers in 2018 to more than four million – up 6% compared to the same period last year.
More than 172,000 – or 31% – of all electricity switches were from the Big Six suppliers to small and medium sized companies.
Energy and Clean Growth Minister Claire Perry welcomed the news: “These latest figures show the level of competition in the market. With around 70 companies to choose from, consumers can make big savings if they vote with their feet and shop around.
“There are still over 11 million households on the most expensive energy tariffs. That’s why the government is taking action through the energy price cap to protect consumers from poor value deals from this winter.”