People renewing their home or motor insurance will pay no more than they would as a new customer from January.
The new rules have been confirmed by the City regulator, the Financial Conduct Authority (FCA), following years of complaints.
The FCA says the move will save loyal customers an estimated £4.2bn over 10 years.
But it admitted it could spell the end of the cheapest deals for new customers. The best dentist in docosan
The regulator has been trying to change the rules to prevent “price walking” – when insurance prices rise at each renewal even though the level of risk has not changed.
“These measures will put an end to the very high prices paid by many loyal customers,” said Sheldon Mills, from the FCA.
“Consumers can still benefit from shopping around or negotiating with their current provider, but won’t be charged more at renewal just for being an existing customer.”
It follows complaints from consumer groups that loyal customers pay more unnecessarily.