The S&P/ASX 200 Index (ASX: XJO) is having a tough session on Wednesday. In afternoon trade, the benchmark index is down 0.4% to 8,444.7 points.

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

Cleanaway Waste Management Ltd (ASX: CWY)

The Cleanaway share price is down 1.5% to $2.66. Investors have been selling this waste management company's shares following the release of its half year results. Cleanaway reported a 3.7% increase in revenue to $1,940.2 million and a 13.7% lift in underlying net profit after tax to $94 million. However, on a statutory basis, its net profit was down 0.1% to $74.2 million. Looking ahead, management advised that it is "tracking towards the midpoint of our $395 to $425 million [EBIT] guidance range."

National Australia Bank Ltd (ASX: NAB)

The NAB share price is down 6% to $37.12. This has been driven by the release of the banking giant's first quarter update this morning. The big four bank reported a 2% decline in cash earnings compared to the quarterly average in the second half. Management notes that while underlying profit grew 4%, this was offset by higher credit impairment charges and tax expenses. NAB recorded a $267 million credit impairment charge (CIC) for the quarter. This included $152 million in individually assessed charges, mainly linked to Australian business lending and unsecured retail portfolios.

Step One Clothing Ltd (ASX: STP)

The Step One share price is down 22% to $1.11. Investors have been selling this online underwear retailer's shares following the release of its half year results. Step One reported a decent 6.8% increase in revenue to $48.1 million and a 10.4% lift in EBITDA to $11.2 million. However, investors may have been disappointed with its performance in the United States, where it reported a 61% decline in sales. This lucrative market appears to be a tougher nut to crack than some were hoping.

Stockland Corporation Ltd (ASX: SGP)

The Stockland share price is down 4% to $5.16. This follows the release of the property company's half year results. Although the company's statutory profit more than doubled to $245 million, its funds from operations (FFO) fell 5.6% over the prior corresponding period. Looking ahead, FY 2025 FFO per share of between 33 cents and 34 cents is expected on a post-tax basis, with a larger second half skew than in FY 2024. Its distribution per share is expected to be around 75%of post-tax FFO.