Global stock markets have now shed US$5 trillion in value in response to the Covid-19 coronavirus. Starting to get alarmed yet?!

Fall back to the advice “Don’t Panic.” I was eight when one of my favorite novels, The Hitchhikers Guide to the Galaxy, came out in 1979. On the cover of that guide, a kind of Lonely Planet for all the planets, are those two reassuring words. We’re told they appear in “large, friendly letters” on a “small, thin, flexible lap computer.”

The hitchhikers guide, a kind of Wikipedia that predated the Internet, has a humorous entry about the planet Golgafrincham. Bear with me, there’s a point here in the end.

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Golgafrincham’s poets were fond of making up stories about how the planet was going to end. Maybe it would be as a result of it crashing into the sun, or the moon crashing into it, or 12′ piranha bees. A tale that it was about to be eaten by a mutant star-goat got its residents to organize three arks: Ark A of leaders and scientists; Ark B of useless people like hairdressers, middlemen and telephone sanitizers; and Ark C of the little people who made stuff and got stuff done. Ark B took off first, sent toward a distant insignificant planet, which turned out to be our prehistoric Earth. The wise folk in Arks A and C stayed put after they got rid of the useless people. Tragically, those Golgafrinchans who remained all died out from an infectious disease contracted from an “unexpectedly dirty” telephone.

Is this our dirty telephone? No, we are the middle managers, lawyers, hairdressers, phone sanitizers. The useless ones. These are 12′ piranha bees. We’re saved!

Back to reality. There are so many unknowns surrounding this disease. I’ve been living with it here in Hong Kong since early this year, having survived through SARS in 2003, too. I caution investors who are worried about the health of themselves and their portfolios to keep a calm head.

Strangely, it has been the sudden emergence of clusters of the disease in South Korea, Italy and Iran that has spooked the markets. These clusters have people the world over rushing to buy industrial-strength face masks, stock up the hand sanitizer, panic-buy canned goods.

Here in Hong Kong, people have been stockpiling rice (which mainly comes here from Thailand, not China), and toilet paper, because a tabloid story said all the toilet paper factories in China would start making masks. I stood today behind an elderly lady buying a US$1 bag of bread, who compulsively reached for the huge stack of toilet paper standing by the checkout. She hesitated, didn’t buy in the end. I could a thought bubble, “If it’s run out, then why is there this huge stack?!”

What investors should be worrying about is the fact that China essentially shut down for more than a month. I’m sorry that almost 3,000 people have died. I’m sorry almost 84,000 people are infected. Here in Hong Kong we have 94 cases, which is 0.001% of the population. Last year, 34,157 Americans died of the flu.

So yes, I am avoiding taking public transportation, and I wear a mask when I’m going to very crowded places. I wash my hands, a lot. But I’m not wearing a mask non-stop. I bet a lot of those 94 infected people wore masks, but took them off at group meals, an apparent source of many infections. If I do get the Covid-19 virus, as a healthy Gen Xer, there’s every chance I’ll survive.

Global manufacturing is going to be stumbling to correct for parts failing to arrive for months to come. Eventually that is going to spill over to other sectors: it’s not much good buying Microsoft (MSFT) shares if Lenovo (LNVGY) has stopped making computers.

Markets hate uncertainty, that’s the cliché, and the situation we find ourselves in is full of them. South Korea now counts 2,337 cases, the most outside China, but at least the Korean peninsula shares an extensive border with China. How it cropped up in Iran and Italy in large numbers is a mystery, and that’s what seems to have finally punctured the protective bubble around investors.

You know the numbers. The S&P 500 has entered technical correction, a drop of 10% or more, faster than ever before. In six trading days, it has come off 12% since last Wednesday’s record high. A record high, one month after Wuhan broke out! We’ll see a few more records broken before this is all over, I’d imagine. The Dow’s 1,191-point fall on Thursday was also a new single-day high.

Asian equities are also ailing. This has been a brutal last trading day of the month, with Japan’s Topix down 3.7%, China’s CSI 300 down 3.6%, Korea’s Kospi down 3.3%, a similar fall for Australia’s ASX 200. These are large single-day falls for markets that have generally been selling off since mid-January.

Not since the Lehman Brothers crisis have we seen such selling. Of course, all asset classes are going to have to contend with virus fallout. Are equities more at risk because they had climbed so high?

Analysts at Goldman Sachs (GS) are predicting that members of the S&P 500 will post no earnings growth at all in 2020. That’s a compound effect from the severe decline in China’s economy, resultant disruption in global supply chains for U.S. companies, and eventually a slowdown in the U.S. economy itself, which is 68% driven by consumer spending.

That seems like a sensible path of calculation. The blanket panic selling, however, isn’t wise. Equally, I think it would be incredibly sad if the Tokyo Olympics this summer got called off.

Bargain-hunting investors should not step into the markets now. There is too much uncertainty, and above all too much herd panic. Day traders on the other hand may find these happy hunting times. Shareholders should be holding companies to account for their exposure to Chinese manufacturing disruption, and chaos in supply chains.

The Hitchhikers Guide has little to say about Earth as a whole. “Mostly harmless” is its entire entry. Covid-19 is a nasty pneumonia, certainly not harmless. But investors should for now fear manufacturing sickness above any infected telephone.