The Federal Court ordered AGL Energy's (ASX:AGL) four units to pay a penalty totaling AU$25 million for breaching the National Energy Retail Rules, according to a Thursday filing with the Australian bourse.

In August, the Court found that AGL Retail Energy and the company's three other units failed to notify and refund about 500 customers within the required timeframes for overcharges obtained from Centrepay payments, the filing said.

The energy company said it has made significant improvements to its processes for handling Centrepay payments since it identified the issue in mid-2020. It would review the judgment closely and consider whether to appeal, it added.

Despite the penalty, the company confirmed that the payment will not affect its fiscal 2025 guidance for an underlying net profit of between AU$530 million and AU$730 million and underlying earnings before interest, taxes, depreciation, and amortization of between AU$1.87 billion and AU$2.17 billion.

Shares of the company fell almost 3% in recent Thursday trade.

Price (AUD): $10.55, Change: $-0.27, Percent Change: -2.54%