The UK's Supreme Court has declined to allow an intervention by Chancellor Rachel Reeves in an important case concerning the transparency of commissions earned on car loans.

Scheduled for a hearing in April 2024, the case will determine whether lenders had a legal obligation to inform customers about the commissions they received from car loan sales.

In a prior ruling, the Court of Appeal stated that lenders should have provided clearer information regarding their commission structures.

However, the lenders have sought to appeal this decision, leading to the Supreme Court's involvement.

The Treasury, which expressed concerns that the Court of Appeal's ruling might adversely impact the availability of car loans, attempted to intervene in the legal process last month.

After the Supreme Court's decision, a spokesperson for the Treasury confirmed its respect for the ruling, stating, "We will monitor it closely."

Most new cars, as well as a significant portion of second-hand vehicles, are purchased through financing agreements.

In response to concerns about pricing transparency, the Financial Conduct Authority (FCA) issued a ban in 2021 on commission structures that incentivized dealers to charge higher interest rates.

Following this, the FCA has begun considering compensation payments for customers affected by these arrangements prior to the ban, raising the potential for banks and lenders to face payouts that could total in the millions.

Last month, a ruling from the Court of Appeal expanded eligibility for compensation, leading some analysts to estimate potential payments reaching up to £30 billion, positioning it as possibly the largest compensation scheme related to financial products since the Payment Protection Insurance (PPI) crisis.

While the government expressed a commitment to ensuring customer redress, it emphasized the need for the automotive sector to remain viable in supporting motorists.

Concerns were raised regarding the potential impact of compensation costs on the competitiveness of UK banks.

The Supreme Court's decision also curtailed intervention applications from Consumer Voice, a compensation advisor, and the Finance & Leasing Association, while it did approve interventions from the FCA and the National Franchised Dealers Association.

Legal experts have noted that it is uncommon for government entities to seek intervention in court cases where they are not a direct party, particularly for policy concerns.

In reaction to the ongoing case, shares in UK banks involved have been negatively affected, with Lloyds Banking Group reporting a decline of 4% and Close Brothers Group seeing a drop of nearly 15% on the stock market.