American artificial intelligence shares are inflating a new technology bubble that will leave British investors feeling foolish, according to stock market pessimists, or “bears”. These worries prompted one financial trade paper to splash with this headline last week: “UK pension funds dump US equities on fears of AI bubble”.

Sadly there was no room in the paper to report that shares in the American aerospace giant Boeing (stock market ticker: BA), which uses quite a lot of technology in its jumbo jets, even if it doesn’t sprinkle AI fairy dust on the investment story, soared 10 per cent that very same day. But your humble correspondent noticed because I first bought Boeing shares at $126 in November 2014, as reported here at that time, and they flew up to $202 on Friday.

To be fair, it has been a bumpy ride. I sold the lot at $410 and $397 in February and March 2019 after two horrific crashes. Then, as millions of people continued to fly around the world and safety fears subsided, I bought back in at $139 in November last year, as also reported here at that time.

Never mind the past, what about the future? Will AI prove to be merely a new form of natural stupidity? The awkward thing to understand is that the bears and bulls — stock market optimists — may both be right.

New technology in general, and AI in particular, is changing the world, mostly for the better. But people who pay too much for shares in some businesses will end up worse off.

There is nothing new about that. Many Victorian middle-class families were ruined when a stock market boom in railway shares, the new technology of its time, went bust in 1847. Even so, the railway network more than doubled in size to about 4,000 miles in the final three years of that boom, and thousands more miles of development were approved by the government — to the long-term benefit of the economy in Britain, which, for context, has fewer than 10,000 miles of railways today.

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Similarly, investors in stock market funds and shares can help to capitalise some of the most exciting and important changes in the way we live now, with apologies to Anthony Trollope, turning science fiction into commercial fact. That’s why I remain cautiously confident about the iPhone-maker, Apple (AAPL), being the most valuable share in my “forever fund”, accounting for just over 8 per cent of the value.

However, as mentioned here before, I believe that diversification is the simplest way to diminish the risks inherent in stock markets. That’s why my life savings are invested in 50 shares, including 20 investment trusts, so I don’t have too much money tied up in any single company, country or currency.

This way they shouldn’t all collapse at once when the inevitable correction or crash arrives. Also, to counter the problem that most technology shares pay low or no income today, instead aiming for capital growth tomorrow, I balance that exposure by owning old-fashioned, long-established businesses that deliver a decent income.

It is important to beware that dividends, or income paid to shareholders, are not guaranteed and can be cut or cancelled without notice. But these cheques may help to keep your humble correspondent warm when winter hits the stock market. That’s why I have recently added three high yielders to the forever fund. While the past is not necessarily a guide to the future, all these businesses survived the Great Depression of the 1930s and two World Wars, which may help if something similar happens next year.

So it is a pleasure to pipe aboard one of the biggest shipping groups in the world, AP Moller-Maersk (MAERSKB). The Copenhagen-listed giant has been afloat since 1904 and yielded nearly 9 per cent gross dividend income when I paid 12,432 Danish krone last month, priced at less than 8.5 times earnings, according to the independent statistician LSEG, formerly London Stock Exchange Group. True, Scandinavian withholding taxes will sink 27 per cent of that income before it reaches me in the Port of London. On a brighter note, LSEG calculates that Maersk increased shareholders’ income by a buoyant annual average of 47 per cent over the past five years. Maersk was priced at 13,250 Danish krone on Friday.

This jolly sailor draws comfort from seeing Maersk’s bright blue containers stacked up in Southampton Docks whenever I pass by. There’s also the fact that nearly 90 per cent of the world’s international trade by volume still goes by sea.

United Parcel Service (UPS) has been in the delivery business since 1907. Despite rapid growth in online shopping it has been dented by industrial disputes and worries about its stated aim to reduce reliance on the digital retailer Amazon (AMZN). The latter is the former’s biggest customer but not its most profitable. While the market waits to see if this transition will deliver — or end up in the wrong postcode — I paid $95 a share, priced at 15 times earnings. UPS shares were unchanged at $95 on Friday.

Its dividend yield of 6.9 per cent arrives without deduction of American withholding taxes because I spent five minutes filling in the single-sheet form W8-BEN. Even more encouragingly, LSEG reckons that UPS increased shareholders’ pay by 11 per cent per annum over the past five years. If that rate of ascent could be sustained, it would double dividends in six years and six months.

While the food giant Kraft Heinz (KHC) was formed by a merger in 2015, Kraft has been pasteurising cheese since 1914 and Heinz has preserved vegetables since 1888. While I would avoid the cheese, all its competitors’ beans, ketchup and tomato soup somehow miss the mark for me. Another attraction of the shares is that I had to pay only $25, while the stock market sage Warren Buffett went in at more than $30 a decade ago. Small shareholders don’t often get the chance to pay less than Uncle Warren. Kraft Heinz shares were $24.70 on Friday.

Shrinking sales and profits have soured this stock since then. Plans to split the business in two have done nothing to lift Mr Market’s mood. Meanwhile, dividend income of 6.4 per cent, albeit without an increase for eight years, might pay me to be patient.

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Ultra-processed food will never be popular with the kale and quinoa brigade, but this old boy can’t be the only one who enjoys the odd tin of soup or beans on toast. I have also been impressed by the new no-salt, no-sugar varieties.

When all three of the businesses above began trading, artificial intelligence came only in the form of books and newspapers. Younger readers may need to google that. Here and now, I hope the shares will continue to yield income, even if AI fails to create capital growth for buyers today. So, as part of a diversified portfolio, I also intend to celebrate my first decade as an Apple shareholder in February.

To return to where we began, bulls and bears can rage about whether AI is a bubble that must burst. Neither group knows for sure. Meanwhile, City cynics say that bears sound clever but bulls make money. You have to be in it to win it.