When Blue Chips Crash

CSL and the myth of the ‘safe’ stock

CSL was untouchable. For two decades, it was the stock every Australian investor pointed to as proof that picking winners works. The biotech darling. The one everyone owned. The one your neighbour mentioned at every barbecue.

In February 2020, CSL hit $342 per share. By May 2026, it was sitting at $125. That’s a 63% decline. Not a speculative tech startup. Not a meme stock. This is CSL, the darling of the market, the bluest of blue chips on the ASX.

What happened?

The short version: CSL paid US$11.7 billion for a Swiss company called Vifor Pharma in 2022. It was supposed to be transformational. Instead, it turned into the third-largest writedown in ASX history.

Total impairments so far: US$6.5 billion. The company’s net profit fell 81% year-on-year. Revenue guidance was slashed. The CEO resigned the day before half-year results. And the share price recorded its largest single-day drop ever, a whopping 20.6%, in a single session in May.

Albumin sales in China dropped 27%. US immunoglobulin revenue fell 6%. Late-stage R&D projects failed. Competitor drugs eroded market share in iron therapy. The vaccine business hit what management called “an extraordinarily difficult operating environment.”

None of this was predicted by the analysts who had CSL as a buy through most of 2024 and 2025. None of it was visible to the retail investors who held CSL as their “safe” stock.

The myth of blue chip

“Blue chip” is not a guarantee. It’s a label. It describes companies that have been large, stable, and profitable for a long time. Past tense. It tells you what a company was. It tells you nothing about what it will be.

CSL was blue chip when it was earning record profits from plasma therapies. It stopped being blue chip when it overpaid for an acquisition, lost key executives, and watched its competitive position erode across multiple product lines simultaneously.

The term creates a dangerous illusion — that certain stocks are inherently safe. That size equals security. That a company with a long track record can’t fail. History says otherwise. Telstra was blue chip. AMP was blue chip. GE was blue chip. Blue chip is a description of the past, not a prediction of the future.

Why individual stocks are the wrong game

CSL’s collapse is not unusual. It’s normal. The SPIVA data tells us this every single year — the majority of professional fund managers, with teams of analysts and billions in resources, cannot consistently pick which stocks will outperform. If they can’t do it, the idea that a retail investor can identify which blue chip will hold its value is optimistic at best.

This is exactly what Eugene Fama’s research explains. Markets are efficient. Prices reflect available information. By the time you know a stock is in trouble, the price has already moved. By the time you read the headline, the damage is done.

The investors who were worst hit by CSL’s decline were the ones who were most concentrated in it. The ones who held it as a significant portion of their portfolio because it felt safe. Because it was blue chip. Because everyone else owned it too.

What a diversified portfolio did instead

While CSL was falling 63%, a globally diversified portfolio was doing what it always does, that is spreading risk across thousands of companies in dozens of countries. Some stocks went up. Some went down. But no single stock had the power to destroy the portfolio.

For example, Dimensional’s World Allocation 70/30 Trust holds over 11,000 securities. CSL is one of them, but just a tiny fraction of the total. So if CSL falls 60%, the portfolio barely notices. That’s not luck. That’s design.

The purpose of diversification is not to avoid losses entirely. It’s to make sure no single loss matters enough to derail your plan. CSL is a textbook example of why that matters.

The uncomfortable truth

If you hold direct shares, particularly in companies you think of as “safe” then CSL should give you pause. Not because those companies are necessarily going to fail. But because you cannot know which ones will. Nobody can. Not the analysts, not the fund managers, not the CEO who resigned the day before results.

In 36 years of giving advice I have spoken with countless people many of whom say, “I only have Blue Chip Stocks”, to me that is a waring bell because I know those portfolio’s are not diversified any where near enough, and a rude shock maybe just around the corner.

The overwhelming evidence says the same thing it has always said. Diversify broadly. Keep costs low. Don’t concentrate in individual stocks, no matter how safe they feel. And don’t confuse a company’s past performance with a guarantee of its future.

Blue chip is a label. It is not a promise.  Not even close.