The S&P/ASX 200 Index (ASX: XJO) is having a subdued session on Wednesday. At the time of writing, the benchmark index is down slightly to 8,140 points.

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

Actinogen Medical Ltd (ASX: ACW)

The Actinogen Medical share price is down 8.5% to 3.2 cents. This morning, this biotechnology company announced the successful completion of an $8.1 million share placement to existing shareholders and new institutional investors. The funds will be used to accelerate the full enrolment of 220 patients with biomarker-positive Alzheimer's disease (AD) in the 36 week placebo-controlled XanaMIA Phase 2b/3 trial being conducted in Australia and the US. In addition, the funds will allow the trial to be administered according to statistical and quality standards required to achieve pivotal status as one of two potential trials required for marketing approval in the US and globally.

Flight Centre Travel Group Ltd (ASX: FLT)

The Flight Centre share price is down 0.5% to $20.75. The catalyst for this has been the travel agent's shares going ex-dividend this morning for its final dividend of FY 2024. Last month, Flight Centre released its full year results and declared a 30 cents per share fully franked final dividend. Eligible shareholders can now look forward to receiving this payout next month on 17 October.

JB Hi-Fi Ltd (ASX: JBH)

The JB Hi-Fi share price is down almost 2% to $79.33. This is despite there being no news out of the retailer today. However, it is worth noting that JB Hi-Fi's shares have been on fire this year. So much so, they remain up 46% year to date despite today's weakness. As a result, it is possible that some investors are taking a bit of profit off the table during today's session.

Nextdc Ltd (ASX: NXT)

The NextDC share price is down almost 1% to $16.85. This morning, this data centre operator announced the launch of its share purchase plan. NextDC revealed that eligible shareholders in Australia and New Zealand can apply for up to a maximum of $30,000 new fully paid ordinary shares at $17.15 per share. This share purchase plan is not underwritten and is capped at $200 million. Unfortunately, NextDC's shares are now trading below the offer price, so it isn't as attractive as its institutional offering was.