IT IS the sort of investment story that makes you cry. If you own shares in Google, the internet search phenomenon, your tears will be of joy.

But if you failed to jump on the most remarkable tech bandwagon investment of the decade, your tears will be bitter. OK, so the shifting value of the US dollar may have taken some of the shine off the returns for sterling or euro-denominated investors. But that is small comfort for missing out on a stock that has injected several extra noughts into that favourite piece of investment terminology: the “go-go” stock.

Larry Page and Sergey Brin, the techno geniuses behind the company, have turned a penchant for mathematical algorithms into a cash colossus. The company they founded in a Californian garage in 1998 with $1 million has a current market value of $210 billion. That puts it on a par with each of Britain’s biggest companies – BP, Vodafone, and HSBC. Since floating on the US Nasdaq stock market three and a half years ago shares have zoomed from $85 to $680. In the past three months, the stock has outrun the Dow Jones industrial average – the benchmark US equity index – by 30 per cent.

If you take your investment guidance from past performance records there is precious little to suggest that Google is anything but an investor’s dream. It is not just in share-price terms that the world’s most famous internet search engine has produced the goods. In its latest financial results, for the three months to 30 September, the company’s revenues jumped 57 per cent and income rose a barely less impressive 45 per cent. Unlike so many of the dot-com starlets that shot to short-lived glory around the turn of the millennium, Google’s success can be counted in hard currency. At the last count Google had amassed $5 billion of net cash.

But just as Google’s powerful and clever search science undermined the value of other memorable web domain names, it, too, could find itself superseded by a follow-on technology. So-called semantic search, for instance, may prove more effective.

At the same time, Google has found some wonderful ways of extending its brand and selling advertising space. The Google Earth mapping feature is a classic. But its ambitions are disconcertingly wide. Everyone, no doubt, would wish it luck in its efforts to discover and promote new clean energy. However, it also suggests that the company is wandering away from what makes it special, and risks taking on adventures that will burn up cash with frightening, and fruitless, rapidity.

Shares in this company, using the conventional price earnings measure, are expensive. They trade at the equivalent of 48 times current year earnings per share. Yes, that multiple may be justified – and suggests Google shares are cheap enough to buy if it maintains the 50 per cent growth rates for at least a couple of years, and manages to grow at 30 per cent, or at least 20 per cent, a year, for ten years after that. If it lives up to these heady expectations, the stock could march right up to $1,000, and beyond. If it does not match these heady hopes, it will be another story.

Google does not pay a dividend, and that leaves the stock bereft of the best kind of crutch should the company hit turbulence. Companies that comply with the tradition of paying dividends subject themselves to a tried, tested and durable management and financial discipline. If they know they have to satisfy investment demand for income, they take enough risks to ensure they can meet realistic expectations but shy away from silly dangers. Young companies, investing hard for future growth, can legitimately delay the payment of income to investors in the interests of conserving capital for investment. Google, whose cash cup brimmeth over, is no in such position.

Google may well continue, for the time being, to deliver handsome share-price growth. But shareholders should not become too dewy-eyed about this company. Unless it proves that it can effectively make a transition into a mature and sustainable business, Google shares are riding for a big fall. And the next move is to sell. robert.cole@thetimes.co.uk