The CSL Limited (ASX: CSL) share price has underperformed the broader market in March despite no negative news from the company.
In fact, only one price-sensitive release from the biotechnology giant hit the market over the last 31 days. Still, the CSL share price has managed to record a gain for the month.
At the time of writing, it's trading at $270, 3.8% higher than it was at the end of February.
For context, the S&P/ASX 200 Index (ASX: XJO) has risen 6.8% over the same period.
So, what's been driving the ASX 200 staple's stock lately? Let's take a look.
What's been driving the CSL share price in March?
There was only one price-sensitive update released by CSL this month – and it managed to send its share price just 0.3% higher.
The news was in regards to the company's US$12.3 billion acquisition of Swiss-listed Vifor Pharma.
News of the acquisition, which spurred a US$4.5 billion capital raise, first broke in mid-December.
The latest update on the transaction dropped on 4 March. Then, the company announced 74% of Vifor Pharma's shares were tendered under its public tender offer.
In response to the acceptance rate, the company waived its previous goal of 80% and declared the offer a success.
The next step the company was to take – a tender period for subsequent acceptance of the offer – was to begin on 9 March and continue until 22 March.
Additionally, CSL stated regulatory approvals were going well and it was confident the acquisition would be finished around the middle of this year.
Unfortunately, the CSL share price tumbled 3.3% the following trading day (7 March). However, the slump wasn't totally unexpected.
That's because CSL traded ex-dividend on 7 March. That means new investors had missed their window to get their hands on CSL's US$1.04 per share unfranked interim dividend.
Generally, shares fall on their ex-dividend dates because the value of their upcoming dividend is no longer attached to their stock.
Finally, the CSL share price took off on 8 March, gaining 2.8% amid news the company's new influenza vaccine had gained regulatory approval to be used in children above the age of two.
However, the company's decent March gains haven't been enough to boost the company's stock back into the long-term green.
The CSL share price is still almost 9% lower than it was at the start of 2022.
