Here’s why GSK and Haleon shares have tanked this week

Shares in both GSK and its spin-off Haleon have plummeted this week. Edward Sheldon looks at what’s going on and whether this is a buying opportunity.

| More on:

The content of this article was relevant at the time of publishing. Circumstances change continuously and caution should therefore be exercised when relying upon any content contained within this article.

Older Man Reading From Tablet

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More.

It’s fair to say it’s been a bad week for both GSK (LSE: GSK) and Haleon (LSE: HL) shares. After starting the week at 1,667p, GSK has fallen to around 1,430p. Spin-off Haleon, meanwhile, has fallen to around 266p after beginning the week at 308p.

So, what’s going on with these two UK stocks? And has the recent share price weakness provided a buying opportunity for me?

Why GSK and Haleon are down this week

The reason the two companies have seen their share prices fall this week is that investors are concerned about US litigation related to Zantac, a heartburn drug. Zantac – which was originally marketed by a forerunner of GSK – was withdrawn from shelves in 2019 after being linked to cancer.

According to Credit Suisse, more than 2,000 lawsuits have been filed in the US (against a number of healthcare companies that sold the drug), with the first trial beginning later this month. And analysts at Morgan Stanley say the total damages could be as high as $40bn.

I’ll point out that this is not exactly new news. The issue has been rumbling on in the background for several years now and in its recent prospectus, Haleon highlighted the risk of potential lawsuits. However, the litigation has received more media attention lately, and as a result, investors have panicked.

I think the panic … really comes down to market psychology as opposed to having learned anything new,” wrote Barclays analyst Emily Field in an email earlier this week.

Zantac statements

It’s worth noting that both GSK and Haleon have released statements regarding Zantac litigation today.

It its statement, GSK said:

  • Based on investigations and experiments, GSK, the US Food & Drug Administration (FDA), and the European Medicines Agency all independently concluded that there’s no evidence of a causal association between Zantac and the development of cancer.
  • Plaintiff litigation is inconsistent with the scientific consensus and the company will vigorously defend all claims.

Meanwhile, in its statement, Haleon said:

  • It’s not aware of any material developments in relation to the Zantac litigation since the Haleon prospectus was issued in June.
  • It’s not a party to any of the Zantac claims.

These statements suggest to me that both companies believe that they’re in the clear here.

Is this a buying opportunity?

After the recent share price falls, both GSK and Haleon trade at relatively low valuations. GSK trades at around 11 times this year’s forecast earnings while Haleon trades at around 15. So, there could be some value on offer here. However, given the uncertainty over the litigation, I’m not convinced the risk/reward is so attractive right now.

Looking past the potential litigation, there are other issues that concern me. GSK has lost its consumer health business, which was the area of the business I liked the most due to its stability. Without this, revenues could be more volatile.

Meanwhile, Haleon has a huge debt pile, which is an issue in a rising-interest-rate environment. Additionally, GSK and Pfizer plan to sell their Haleon shares when the lock-up period ends in November. This could put pressure on the share price.

All things considered, I think the best move, for me personally, is to leave these two stocks alone for now and focus on better, safer opportunities.

Edward Sheldon has no position in any of the shares mentioned. The Motley Fool UK has recommended GSK plc and Haleon plc. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.

More on Investing Articles

Investing Articles

Is Alphabet still one of the best shares to buy heading into 2026?

The best time to buy shares is when other investors are seeing risks. Is that the case with Google’s parent…

Read more »

Investing Articles

Could the Barclays share price be the FTSE 100’s big winner in 2026?

With OpenAI and SpaceX considering listing on the stock market, could investment banking revenues push the Barclays share price higher…

Read more »

Investing Articles

Will the Nvidia share price crash in 2026? Here are the risks investors can’t ignore

Is Nvidia’s share price in danger in 2026? Stephen Wright outlines the risks – and why some might not be…

Read more »

Middle-aged white man pulling an aggrieved face while looking at a screen
Growth Shares

I asked ChatGPT how much £10,000 invested in Lloyds shares 5 years ago is worth today? But it wasn’t very helpful…

Although often impressive, artificial intelligence has its flaws. James Beard found this out when he used it to try and…

Read more »

Portrait of pensive bearded senior looking on screen of laptop sitting at table with coffee cup.
Investing Articles

Did ChatGPT give me the best FTSE stocks to buy 1 year ago?

ChatGPT can do lots of great stuff, but is it actually any good at identifying winning stocks from the FTSE…

Read more »

Surprised Black girl holding teddy bear toy on Christmas
Investing Articles

Who will be next year’s FTSE 100 Christmas cracker?

As we approach Christmas 2025, our writer identifies the FTSE 100’s star performer this year. But who will be number…

Read more »

Businessman with tablet, waiting at the train station platform
Investing Articles

I asked ChatGPT for an 8%-yielding passive income portfolio of dividend shares and it said…

Mark Hartley tested artificial intelligence to see if it understood how to build an income portfolio from dividend shares. He…

Read more »

Female student sitting at the steps and using laptop
Investing Articles

How much do you need in an ISA to target £8,333 a month of passive income?

Our writer explores a potential route to earning double what is today considered a comfortable retirement and all tax-free inside…

Read more »