Let's remember that it was a very partial IPO, more designed to bail out the parent company's coffers than to really let the jewel in the crown emancipate itself: Volkswagen still holds 75.4% of the capital, and the Porsche-Piëch family 12.5%; this leaves only a tiny free float, with no voting rights to boot.

If the successful listing of Ferrari - separated from Fiat in 2016, and now controlled by Exor and the founding family to the tune of one third of the capital - has of course served as a model, the two configurations differ: Porsche indeed remains closely linked to VW, both in terms of governance and industrial integration.

Everyone will assess the situation according to their own intuition: some investors will regret the obvious risk of conflict of interest; others, on the contrary, will be pleased that Porsche can benefit from the synergies offered by the scale of the world's leading manufacturer.

If VW follows the recipe of partial IPOs - very fashionable in Germany - as practiced by Bayer or Siemens, it does not seem unreasonable to expect a gradual disengagement on its part, which everyone should welcome. This is a matter to be followed.

In terms of accounts, Porsche's sales have increased significantly over five years, from €25.8 to €37.6 billion - a growth of 46% - while the net margin hovers around an average of 11.5%. A quarter of the turnover is generated in the United States, a little less than a third in China.

On a much smaller scale, Ferrari did significantly better: its sales rose from €3.4 to €5.1 billion - a growth of 50% - with an average net margin of almost 20%. One fifth of the turnover is realized in the United States, a little more than a tenth in China.

At €110 a share, Porsche is valued at 20 times its profits, half as much as Ferrari at 40 times its profits. Locked governance, limited free float and a net margin more "premium" than "luxury" explain this difference.

This last point is also open to interpretation. Some will argue that the Italian is playing a game above the German, in a genuine prestige segment, while the latter deserves to be compared to Tesla. A multiple of luxury - such as x40 the profits - would be disproportionate.

Others, on the contrary, will see in Porsche an astonishing ability to serve the premium and ultra-luxury market segments, and will point to the manufacturer's long tradition of success in launching new models. In this, Ferrari would remain very exclusive, while Porsche would combine the best of both worlds.

Where opinions do not differ, however, is on the fact that an expansion of margins and a gradual exit from VW would undoubtedly be very well received by the market.