CSL began as a government laboratory making vaccines for Australians. Today it is a global biotech giant built on donated blood plasma. Here’s how it makes its money, and why it has hit a rough patch.
CSL is Australia’s largest biotechnology company and one of the biggest companies on the ASX.
It started in 1916 as the Commonwealth Serum Laboratories, a government body set up to make vaccines and medicines for Australians. It was privatised and listed on the ASX in 1994, and has since grown into a global business that sells its medicines in more than 100 countries.
CSL reports in U.S. dollars, because most of its sales are overseas. In the year to June 2026, it reported revenue of US$15.8 billion and underlying profit of US$3.1 billion.
Plasma, vaccines and iron
The biggest part of the business is CSL Behring, which brought in about US$11.4 billion of revenue in the 2026 financial year.
It collects plasma, the liquid part of blood, from donors at collection centres, mostly in the U.S. The plasma is then separated into proteins and turned into treatments. Its most important products are immunoglobulins, which help people with weakened immune systems fight infection, along with albumin and treatments for bleeding disorders such as haemophilia.
Plasma medicines are expensive and difficult to make, and collecting plasma takes a large network of centres, so there are only a handful of major producers worldwide.
CSL Seqirus is one of the world’s largest makers of flu vaccines. It also makes vaccines in Melbourne for Australia, including for pandemics. CSL had planned to split it off into a separate company, but delayed that plan in October 2025.
CSL Vifor, bought in 2022 for about US$11.7 billion, sells treatments for iron deficiency and kidney disease.
A difficult 2026
CSL’s 2026 financial year was a reset. It posted a statutory loss of US$2.6 billion after restructuring costs and write-downs, including on the value of the Vifor business, where some products are facing cheaper generic competition.
Chief executive Paul McKenzie retired in February 2026, and long-time senior executive Gordon Naylor was appointed interim chief executive. The company is cutting costs, closing some underperforming U.S. plasma centres and reducing its workforce.
The risks include the cost of collecting plasma, competition from new drugs that could reduce demand for some plasma treatments, pricing pressure from governments, and changes to health policy in the U.S., its biggest market.
CSL remains one of the most widely held shares in Australia, and investors are watching closely to see whether its restructuring returns it to growth.
