By Rajasik Mukherjee

April 23 (Reuters) – Australian biotech giant CSL extended losses on Thursday, lingering near decade lows, after the U.S. military scrapped its flu vaccine mandate, dealing ‌another blow to the drugmaker as it grapples with a prolonged earnings slump.

The ‌U.S. defense department said on Tuesday that military personnel would no longer be mandated to receive the flu vaccine, ​marking a reversal from a long-standing requirement and raising concerns about demand from a key institutional buyer.

“The Pentagon’s move… was a meaningful catalyst for the sell-off and could be the straw that finally breaks the camel’s back,” said Marc Jocum, senior product and investment strategist at GlobalXETFs.

“CSL was ‌already carrying a heavy load ⁠around falling U.S. flu vaccination rates, weaker Seqirus earnings, and delayed strategic plans, and this decision simply adds incremental pressure at the worst possible ⁠time.”

The stock fell as much as 0.8% to its lowest since late August 2017, bringing its yearly decline to over 25%.

CSL is heavily exposed to the United States, its largest revenue source, according ​to its ​annual report.

The firm’s vaccines business – which includes influenza ​shots supplied through unit CSL Seqirus – ‌is one of its most profitable divisions.

CSL Seqirus generated about $2.17 billion in revenue in fiscal 2025 – about 14% of the company’s total.

The stock had already been under sustained pressure amid slowing demand for plasma-derived therapies, higher collection and manufacturing costs, and multiple earnings downgrades over the past year.

CSL, a former government laboratory which later became a stock market darling, has also ‌been at the receiving end of investors’ wrath over ​its share price performance. Once Australia’s priciest stock, CSL ​plunged about 39% last year in ​its biggest annual drop since 2002.

Investors have also grown wary of the ‌pace of recovery in CSL’s core plasma ​business, which was badly ​disrupted during the pandemic.

“The real issue runs deeper: slowing earnings momentum, a more volatile vaccine segment, and a lack of clarity around the company’s forward strategy,” said Hebe ​Chen, market analyst at Vantage ‌Markets.

“A 5% drop (on Wednesday) of this magnitude signals the market is still repricing ​that broader confidence gap, with CSL yet to convincingly find a floor.”

(Reporting by ​Rajasik Mukherjee in Bengaluru; Editing by Kim Coghill)