News that the Facebook founder Mark Zuckerberg might take a stake in one of my biggest shareholdings sent its price surging 7 per cent higher on the day, despite double-digit losses elsewhere in last week’s stock market “tech wreck”.

The microchip makers Nvidia (stock market ticker: NVDA) and Intel (INTC) plunged from peak valuations by 22 per cent and 57 per cent respectively on fears that artificial intelligence (AI) might disappoint.

Even rising revenues and profits at the iPhone-maker, Apple (AAPL), and software giant Microsoft (MSFT), my most valuable and ninth-most valuable holdings respectively, were not enough to prevent their share prices slipping 6 per cent and 13 per cent below recent peaks. Hopes that AI features might be added to new iPhones as soon as next month, prompting some of the 270 million customers who have not bought a new one for four years or more (including me) to upgrade, helped support AAPL’s price, which remains 20 per cent higher than it started this year.

More generally, Mr Market has lost his taste for digital tales of jam tomorrow. However, one of my more esoteric shares is proving to be an important exception to that trend.

EssilorLuxottica (EL) is not a household name in Britain, but this €95 billion Franco-Italian giant makes nearly a third of the optical lenses in the world. That’s why I paid €96 in March 2019, as reported here at that time, for shares that cost €209 at the close of business on Friday and are my sixth most valuable holding.

My original reason for investing was that fewer folk are willing to put up with poor eyesight, which used to be regarded as part of growing old, now that we spend so much of our lives looking at small screens on computers and phones. So an ageing, online and wealthier population is likely to buy more eyewear for the foreseeable future.

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That long view came into sharp focus four years ago when EL teamed up with Facebook’s parent company, Meta Platforms (META), to make “smart glasses” that now enable users to take photos and videos, listen to music, take calls and live stream online. The version on sale in America also includes access to Meta’s artificial intelligence assistant, so wearers can ask for more information about whatever they are looking at.

Unlike earlier “wearable technology”, the digitally enhanced specs look just like any other sunglasses. More specifically, they are the latest iteration of the long-established Ray-Ban Wayfarer, which is probably EL’s best-known brand alongside Oakley. So buyers of the new kit can hope it makes them look less “geeky nerd” and more like Muhammad Ali, the charismatic fighter who helped these shades to become global bestsellers.

This year EL extended the new technology aspect of its eyewear by launching glasses that double up as inconspicuous hearing aids, addressing another widespread disadvantage of old age. The online video glasses are called Ray-Ban Meta and the hearing glasses are dubbed Nuance Audio.

Then stock market chatter began to suggest that Meta might buy a stake in its eyewear partner. Zuckerberg told analysts in April: “If we want everyone to be able to use wearable AI, eyewear is a bit different from phones or watches in that people are going to want very different designs. So I think our approach of partnering with leading eyewear brands will help us serve more of the market.”Last month Francesco Milleri, chief executive of EL, told institutional analysts that Meta had contacted him to discuss becoming an investor. He added: “We are informed of this kind of intention. We are proud that the company that know us very well now after years of partnership is convinced that our company, our group, can grow.”

Here and now, this business enjoys a gross profit margin of 64 per cent and sits on cash reserves of €598 million. Although the dividend yield is a modest 1.9 per cent, payouts to shareholders increased by an annual average of 14 per cent over the past five years, according to the independent statistician LSEG Data & Analytics.

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It is important to remember that dividends are not guaranteed and can be cut or cancelled without notice. However, if EL’s rate of increase in payouts to shareholders proves sustained, that would double our income in five years.

So this business looks like an attractive combination of one that meets real human needs, already makes good profits and has the exciting potential for new technology to create additional products and profits in future. Against all that, there is always the risk that a competitor will find a way to make something similar, better and cheaper.

Most immediately, the shares are no longer cheap, having doubled since I first told you about them, and are now priced at an eye-stretching 41 times corporate earnings. That still remains lower than the price/earnings (P/E) ratios of NVDA, the online retailer Amazon (AMZN), and the electric car company Tesla (TSLA), where — despite last month’s double-digit price slumps in all three shares — the P/E ratios remain 53, 68 and 63 respectively.

So I think there might be further to go for this Franco-Italian firm, making high tech specs. It’s the exceptions that make investing interesting. Or is this happy shareholder looking through rose-tinted glasses?

A tale of two sales slumps

Food and drink will never go out of fashion, although investing in them is not risk-free, as two shareholdings reminded me last week. Both businesses blamed cash-strapped consumers for falling sales, but their share prices reacted very differently.

Let’s do the bad news first, because I know some of you enjoy my pratfalls more than my profits. The drinks giant Diageo (DGE) reported sales only 1.4 per cent lower in the year to June, its first shrinkage since the Covid crisis, but the share price slumped by 7 per cent.

I am not crying into my beer because I transferred DGE shares from a paper-based broker into the “forever fund” at £21 in September 2013, as reported here. Even after the price has nearly halved in two terrible years, they still trade at £23.77 with a 3.4 per cent dividend yield.

Then the world’s biggest fast-food business, McDonald’s (MCD) also reported its first sales decline since Covid, but the share price actually went up by 4 per cent on the day. This is my fourth-biggest shareholding, since I paid $95 in July 2014, as reported here at that time, for shares that cost $272 on Tuesday and still yield 2.5 per cent dividend income.

Many factors played a part in these different outcomes but here’s one neither business mentioned. MCD can rely on millions of US shareholders, investing to pay for retirement, who are happy to “buy on the dip”. DGE has a smaller fan club of retail investors, who suffer stamp duty, or a tax on share purchases, that is absent in America.

That’s two reasons why I tend to favour Yankee blue chips over the Brits. It also illustrates the importance of investing internationally to diminish risk by diversification.

Full disclosure: Ian Cowie’s shareholdings