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The 'Big Six' energy suppliers

The 'Big Six' may be a term you have heard before, and it refers to the largest six energy supplliers on the market.

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The 'Big Six' energy suppliers
Whole of market comparison

Whole of market comparison

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Save up to £350 on your energy bills**

Save up to £350 on your energy bills**

Who are the 'Big Six' energy suppliers?

The Big Six currently supplies almost 95% of British households with gas and electricity. The Big Six includes:
  • British Gas - the energy company with the largest energy market share in the UK, supplying over 11 million homes with gas and 6 million with electricity. It is a subsidiary of the UK-based Centrica group, which also owns Scottish Gas.

  • EDF Energy - supplies gas and electricity to 6 million homes. It is the largest producer of electricity in the UK.

  • E.ON - provides energy to around 7 million homes and is owned by German E.ON AG. Prior to its 2002 acquisition it was known as Powergen.

  • Npower - supplies around 5 million homes with energy. Having begun life as Innogy, it was purchased by German RWE in 2002.

  • Scottish Power - has around 5 million residential customers. It was acquired by Spanish-based Iberdrola in 2006.

  • SSE - the second-largest energy supplier in the UK, SEE (or Scottish and Southern Energy) have almost 9 million customers. It’s a Scottish-registered company trading on the London Stock Exchange, and a major hydro and wind energy producer.
Although the 'Big Six' currently supplies almost 95% of British households with gas and electricity, there are a number of smaller energy suppliers who could potentially offer you a better energy deal on your gas and electricity, in order to gain attention and attract more customers away from the Big Six.

What are the dangers of an energy market dominated by the 'Big Six' suppliers?

The economy of the UK is built the principal of its markets being competitive. In practice, this means that the more companies that exist within a certain sector, the more competition there will be between these firms. The more competition there is, then the more pressure there is on these firms to compete with each other to offer their customers the best energy deals possible in order to keep their existing customers - and attract new ones away from their rivals.

There is a worry, when just six companies dominate any market, that competition can suffer. However, whilst there have been many reviews into the behaviour of these Big Six energy companies, none of them have yet found these companies guilty of any wrongdoing. Both the FCA (Financial Conduct Authority) and Ofgem (the regulator of the energy markets in the UK) concluded that all of these companies had acted reasonably and responsibly, with regard to the setting of their prices.

The energy watchdog stated: "It has been concluded that no evidence of the alleged market manipulation could be found and therefore that the interests of consumers have not been harmed."

Should you switch to a small supplier?

If you are worried that you might not be getting the best energy deal from your gas and electricity supplier, and want to help do more to increase the competitiveness of the UK energy market, then it is certainly worth you having a look at one of the many smaller suppliers out there.

These companies offer a viable alternative to those companies in the Big Six, and it could be cheaper for you to switch energy to one of them as they may offer lower prices or different perks. Typically, smaller suppliers fare better when rated for their customer service, for example.

There are also several smaller suppliers, including Bulb and Green Star, who focus on providing mostly or entirely renewable energy. Energy providers like these can be a great alternative to the Big Six if you’re environmentally-minded.

Small energy suppliers often offer deals on par with, or in some cases cheaper than, the Big Six. It is worth investigating them to see if you could make a saving on your energy bill if you switch energy to one of them; you and increase your levels of customer satisfaction, with another company.

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**£350 is the average saving achieved by 10% of all customers who switched their dual fuel supply in 2019 via our partner energy journey

Last reviewed: 10 November 2020

Next review: 10 December 2020