CSL shares (ASX: CSL) surged as much as 18% on Tuesday, capping the biotech giant's best single session in more than two decades.
The stock changed hands around $157.40.
That is an extraordinary move for a company of this size, and it becomes stranger still once you read the headline numbers.
CSL reported a net loss after tax of US$2.6 billion for FY26.
A record loss and a record rally, on the same morning.
So what did the market see that the headline missed?
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Why CSL shares looked past a US$2.6 billion loss
The loss was not in any way an operating problem.
It came from US$7.1 billion in pre-tax impairments and a further US$799 million in restructuring costs, none of which involved cash leaving the business.
Most of that writedown was due to CSL Vifor intangibles and under-utilised property, plant, and equipment.
Investors had also been warned well in advance, because back in May the company flagged roughly US$5 billion of impairments alongside a cut to FY26 guidance.
Strip the one-offs away and the underlying picture was far steadier.
Underlying NPATA stood at US$3.1 billion, down just 2% on the prior year.
Revenue of US$15.8 billion slipped 1%, but still came in ahead of what most analysts had predicted.
Operating cash flow was a healthy US$3.5 billion.
Inside the FY26 result
CSL Behring remains the engine room of the business.
The plasma division generated US$11.4 billion in revenue, down 1%, while immunoglobulin sales held flat at US$6.2 billion.
That immunoglobulin line is a key pillar of the CSL bull case.
CSL Vifor lifted 3% to US$2.4 billion.
Seqirus was weak, with the influenza vaccine business shrinking 8% to US$2 billion.
In better news, CSL's transformation program delivered US$176 million of cost savings during the year.
Management also committed US$1.5 billion to expanding plasma collection capacity across the United States.
The final dividend left the full-year payout unchanged at US$2.92 per share.
The guidance that drove the CSL share price craze
Here is where the enthusiasm came from.
CSL guided to underlying NPAT growth of approximately 5% in FY27.
Consensus had been sitting closer to 2%, so for a company that has spent 18 months walking its guidance backwards, an upgrade of any kind is a welcone plot twist.
Behring is expected to grow at a mid-single-digit rate, with immunoglobulins running in the mid-to-high single digits.
The offset is CSL Vifor, where revenue is tipped to fall around 25% as iron generics arrive.
Interim chief executive Gordon Naylor set the tone for this reset back in May.
Growth initiatives are working, but the financial benefits will take longer than previously anticipated to materialise.
Are CSL shares still worth a look?
Even after Tuesday's surge, CSL shares remain down roughly 8% in 2026, and they still sit well below the highs they set a few years ago.
Investors should still be considering the bear case. The company is still operating without a permanent chief executive, Seqirus is shrinking, and the Vifor acquisition has now been written down heavily.
One guidance beat does not undo two years of disappointment.
Ahead of the result, my Foolish colleagues asked whether the healthcare giant could arrest the slide.
On the evidence of a single session, the answer is yes. However, sustaining this recovery is a very different question.
Foolish takeaway
Tuesday was not really a case of the market missing something.
It was a case of the market finally being handed something to hold onto: a reset year, a cleaner balance sheet, and guidance that beat expectations for the first time in a while.
The plasma business is still growing, and the cost program is still delivering.
Whether CSL shares can build on that will come down to execution over the next 12 months.
