In afternoon trade, the S&P/ASX 200 Index (ASX: XJO) is on course to record a solid gain. At the time of writing, the benchmark index is up 0.8% to 8,387.5 points.

Four ASX shares that have failed to follow the market higher today are listed below. Here's why they are falling:

Megaport Ltd (ASX: MP1)

The Megaport share price is down over 10% to $7.47. Investors have been selling this network as a service provider's shares after it only reaffirmed its guidance for FY 2025. It seems that the market was expecting an upgrade or strong commentary on its FY 2026 outlook. Management advised that it continues to expect FY 2025 revenue of $214 million to $222 million. This represents a 9.6% to 13.7% year-on-year increase. EBITDA is still expected to be between $57 million and $65 million, which is flat to 14% higher year over year. Looking further ahead, management said that "early trends are indicative of a continuation of this revenue growth trajectory into FY26."

Pilbara Minerals Ltd (ASX: PLS)

The Pilbara Minerals share price is down almost 3% to $2.72. This is despite there being no news out of the lithium miner. However, it is worth noting that Pilbara Minerals' shares have taken a beating this week. This latest decline means that they are now down by 11% since this time last week.

Vysarn Ltd (ASX: VYS)

The Vysarn share price is down 10% to 39 cents. This follows the release of the end-to-end water services provider's annual general meeting update this morning. Vysarn advised that it expects its earnings to fall half on half during the first half of FY 2025. This is due to ongoing conservatism within the Western Australian resources sector as a result of the broader global economic and political environment, and consequential uncertainty in commodity prices. However, it does expect a major improvement in the second half to drive sustained earnings growth in FY 2025.

WiseTech Global Ltd (ASX: WTC)

The WiseTech Global share price is down 9.5% to $125.73. Investors have been selling this logistics solutions provider's shares after it downgraded its guidance for FY 2025. Due to distractions flowing from the recent media attention over ex-CEO Richard White's behaviour and the organisational changes that have subsequently been implemented, the commercial launch of its new Container Transport Optimization has been delayed. As a result, revenue and EBITDA are expected to be $1,200 million to $1,300 million and $600 million to $660 million, respectively, in FY 2025. The midpoint of these guidance ranges represents a downgrade of 5.7% and 7.4%, respectively, from its previous guidance.