A consumer advocacy group in the U.K. is calling on policymakers to consider adopting a rule that would require financial firms to automatically switch clients from underperforming products into better alternatives, after uncovering the high cost of being stuck in poor products.

The U.K.’s Financial Services Consumer Panel (FSCP) published new research on Tuesday that found that long-term financial firm clients pay a “loyalty penalty” when they don’t shop around for better products.

The research, which was conducted by Europe Economics, found that some consumers are paying loyalty penalties that represent 5% of annual income, and possibly as high as 10% for certain clients who are stuck in poor products.

“Our results show that the costs of remaining in poorly performing products can represent a notable proportion of consumers’ annual incomes,” the paper said.

It examined a variety of products, including mortgages, investments and insurance.

The worst offenders, according to the research, were mortgages and credit cards; whereas poor-value investments and bank accounts impacted specific demographic groups examined in the research.

The sorts of customers who are likely to be hardest hit, the research found, are likely to have average incomes, a range of standard financial products and relatively large amounts of debt.

“The research demonstrates the detriment for consumers of remaining in poorly performing products and the need to ensure that all consumers are treated fairly,” said Wanda Goldwag, chair of the FSCP.

To that end, the FSCP is calling on the U.K.’s Financial Conduct Authority (FCA) to consider adopting a rule that would require firms to automatically move clients out of poor value products, and into better options.

“Loyal customers are often those who are too busy to search for and switch to better products, those who do not switch due to behavioural biases, those trapped with their existing provider or those who are not aware that better alternatives exist. Consumers should not be penalised for this loyalty,” she added. “An automatic-upgrade rule would level the playing field.”