It has been a difficult session for the S&P/ASX 200 Index (ASX: XJO). In afternoon trade, the benchmark index has followed Wall Street's lead and dropped deep into the red. At the time of writing, the benchmark index is down 1.3% to 7,785.3.

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

The Mesoblast share price is down 9.5% to 86 cents. This is despite there being no news out of the biotechnology company. However, with its shares flying high in recent sessions, it seems quite likely that some profit taking is happening today. After all, Mesoblast's shares remain up over 100% since this time last week despite today's pullback. This strong gain was driven by the US Food and Drug Administration advising that there appears to be sufficient results to support the submission of the company's proposed Biologics License Application (BLA) for its remestemcel-L medicine to treat paediatric patients with steroid-refractory acute graft versus host disease.

The Regis Resources share price is down 3% to $1.95. Investors have been selling this gold miner's shares after it released an update on the McPhillamys Gold Project in New South Wales. Regis Resources advised that substantial progress has been made towards completion of the Definitive Feasibility Study (DFS) for the project. However, as the DFS has progressed, it has now become apparent that its development costs will be higher than anticipated and previously communicated.

The Westgold Resources share price is down 14% to $2.37. This has been driven by the release of the gold miner's quarterly update this morning. During the quarter, Westgold produced 52,100 ounces of gold and achieved an average gold sale price of $3,137 per ounce. The former was softer than expected and has led to management downgrading its FY 2024 production guidance range to 220,000 to 230,000 ounces.

The WiseTech Global share price is down 5% to $89.89. This is despite there being no news out of the logistics solutions technology company. However, the tech sector is a sea of red on Wednesday following a poor night of trade on the Nasdaq index. Investors appear to have been spooked by the prospect of interest rates staying higher for longer. In afternoon trade, the S&P/ASX All Technology Index is down a disappointing 2.6%. This is twice the size of the market decline today.