Comparison sites are facing an investigation by the Financial Conduct Authority (FCA) to ensure consumers are not "being misled".
The review will focus on 14 websites covering 90% of the market.
The FCA said while comparison sites had made it easier for consumers it would investigate potential risks, including that consumers may not fully understand the services provided by the websites and may be misled into buying products or add-ons that do not meet their needs.
It also highlighted that consumers could be treated unfairly if sites focus on generating profits, do not enough oversight of the firms/products they display or are not aware of any possible conflicts of interest.
Commenting on the investigation, Peter Plumb, chief executive of MoneySupermarket.com plc, said: "As an independent price comparison site our business model is aligned with the FCA s objectives. We welcome their review and any regulation which is good for customers
"Customers have different needs, nearly half our customers do not buy the cheapest product on the market and prefer to select on features or brand.
"We are a free service to our customers, we do not receive a commission for our services we do however receive a small flat fee for every customer who buys a policy which is completely independent of policy value."
The results will be published next year.
