The S&P/ASX 200 Index (ASX: XJO) is a sea of red on Thursday following a selloff on Wall Street overnight. In afternoon trade, the benchmark index is down 1.8% to 8,157.8 points.

Four ASX shares that are falling more than most today are listed below. Here's why they are dropping:

AGL Energy Limited (ASX: AGL)

The AGL Energy share price is down 3% to $10.50. Investors have been selling this energy retailer's shares after revealed a $25 million penalty. According to the release, the Federal Court has ordered that four AGL subsidiaries pay a total penalty of $25 million in proceedings brought by the Australian Energy Regulator (AER). The Federal Court determined that AGL breached the National Energy Retail Rules by failing to notify and refund approximately 500 customers within the required timeframe in relation to Centrepay payments. The good news is that AGL's FY 2025 guidance remains unchanged despite this penalty. It still expects underlying EBITDA between $1,870 million and $2,170 million and underlying net profit between $530 million and $730 million.

Commonwealth Bank of Australia (ASX: CBA)

The CBA share price is down 2% to $156.52. This has been driven by broad weakness in the banking sector today following last night's selloff on Wall Street. Investors were hitting the sell button after the US Federal Reserve cut interest rates but indicated that fewer than expected cuts were coming in 2025. This could mean higher than expected borrowing costs for CBA next year.

Deep Yellow Ltd (ASX: DYL)

The Deep Yellow share price is down 12% to $1.05. This morning, this uranium developer released an update on its Tumas project. According to the release, the company has delayed its final investment decision on the project until early March 2025. Management advised that this is due to delayed costings and quotes for equipment and construction, and further project optimisation. Deep Yellow's managing director, John Borshoff, adds: "[T]he current long-term uranium price does not reflect what we see as a significant emerging supply shortage."

Megaport Ltd (ASX: MP1)

The Megaport share price is down 10% to $7.48. This is despite there being no news out of the network as a service operator. However, it is just one of a number of ASX tech stocks that are sinking on Thursday following a selloff on the Nasdaq index. For example, the selling in the sector means that the S&P/ASX All Technology Index is down 3% on Thursday afternoon.