Updates with share moves in paragraphs 2, 3, analyst quotes in paragraphs 7, 8, 13

By Rajasik Mukherjee

May 11 (Reuters) - Australian biotech firm CSL CSL.AX slashed its fiscal 2026 outlook on Monday citing delays in returns from growth initiatives and headwinds from normalisation of U.S. immunoglobulin inventory, and flagged a $5 billion impairment charge, sending its shares to a near decade-low.

Shares of the firm fell as much as 17.8% to A$98.590, their lowest level since January 19, 2017.

So far in 2026, CSL has lost over 40%, a sharp contrast to the ASX top 20 index .ATLI, which is up over 4.5% so far this year.

On Monday, the firm's interim CEO, Gordon Naylor, said he had conducted a review of the business after taking on the role in February and that the financial benefits from CSL’s growth initiatives had yet to materialise.

CSL, a former government laboratory that became a stock market darling, said it expects to recognise about $5 billion in non‑cash, pre‑tax asset impairments across fiscal years 2026 and 2027, including writedowns of CSL Vifor intangible assets such as parts of its product portfolio.

For 2026, CSL now expects a net profit after tax attributable, excluding restructuring costs and impairments, of about $3.1 billion on a constant-currency basis, compared with $3.3 billion reported a year earlier.

"On the guidance cut - this is the second trim in roughly six months, and that pattern matters," said Mark Gardner, founder and CEO of MPC Markets.

"Back-to-back downgrades do raise legitimate questions about the company's visibility into its own business."

In August last year, the firm projected its 2026 NPATA to be in the range of $3.45 billion to $3.55 billion, representing growth of about 7-10%.

The company also cut its fiscal 2026 revenue forecast to $15.2 billion on a constant-currency basis, compared with $15.6 billion reported last year.

CSL said its revised revenue outlook reflects an estimated $300 million hit to revenue from U.S. immunoglobulin channel inventory normalisation, about $200 million from lower albumin market value in China, and roughly $150 million from the impact of the Middle East conflict and other headwinds.

The forecast downgrade comes at a time when CSL 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.

"The broader picture is a firm in the middle of a complex transformation - still without a permanent CEO, dealing with the fallout of an overpriced acquisition, and navigating real revenue headwinds in its two biggest markets," Gardner said.

Last year, in October , the company cut its NPATA forecast to 4%-7% growth and its 2026 revenue guidance to 2% to 3%, down from a 4% to 5% range.