More details have been announced about the investigation into the credit card market that was first announced earlier this year.
City regulator, the Financial Conduct Authority (FCA), said in April that it was launching an investigation into the workings of the £60 billion market.
The credit card industry has seemed to be in rude health this year, with interest-free terms on balance transfers and purchases cards both reaching record levels.
But the regulator's initial investigation has determined that the credit card market is not working well enough for some of the UK's 30 million cardholders.
Its full inquiry will cover an array of credit card services offered by banks and their brand partners.
The issues covered will include the transparency of terms and conditions, the complexity of credit card products, and the ease with which consumers can compare between them effectively.
The FCA will also mirror the mortgage market by looking more closely at irresponsible lending practices by credit card providers.
Lenders are regularly thought to encourage borrowers to take on extra credit they don't need in order to profit from interest on the larger balances.
The inquiry will investigate whether debt levels have remained high because of credit card marketing or account management techniques that work against the best interests of consumers.
The FCA said it was important to get market conditions right for UK consumers, who hold around almost three quarters of all the credit cards in Europe.
“We want to understand in more depth what drives consumers to make the choices they do and how firms develop the services they offer,” said Christopher Woolard, the FCA's Director of Policy, Risk and Research.
“We want to make sure that the market works well for all consumers and that card-holders get a fair deal.”