Further proof is provided by S4 Capital, the latest investment vehicle of advertising magnate Martin Sorrell - mythical founder of the WPP group, originally Wire & Plastic & Products, a small industrial company he transformed into the world's number two advertising group after a frenzy of acquisitions.

Sorrell was criticized for his feudal management of WPP, before being ousted. Backed by a host of investors, the indefatigable tycoon went straight back to attacking the advertising industry via S4, this time with a 100% digital positioning and a focus on content creation.

It wasn't all success. While the £667 million invested in acquisitions over the eight years of its existence has so far succeeded in "creating" £103 million in operating profit, a decent return on investment on the whole, S4 suffers from a critical growth failure.

Its portfolio of activities focused on content creation - notably for clients in the technology sector - seems dangerously exposed to the rise of artificial intelligence technologies. So, rather than the promised growth, it's a question of decline. As a result, earnings warnings have been piling up, and with them plunges in the share price. In 2024, as in 2023, the business is even expected to post red accounts and burn cash. Nothing reassuring when net debt amounts to x3.5 last year's operating profit.

This news is all the more disturbing given that S4 needs a high share price to make acquisitions, using its stock as a bargaining chip. So the snake is biting its own tail, and the lack of market buying by the Group's executives at these seemingly depressed valuations seems to confirm that the fire is smoldering in the house.