Last year, the Volkswagen Group announced that both its Porsche and Audi brands were planning to enter F1.
Audi's entry is well under way at Sauber.
But while Porsche's attempts to link up as engine partner with Red Bull eventually collapsed, its interest is not dead, and it is still exploring ways it could enter F1.
The other big name in the picture is Ford - GM's biggest rival in America.
Senior sources say it is in talks with Red Bull with a view to a partnership similar to Porsche's original plan, and could later expand into its own team entry.
With Porsche and Ford in the picture, the Andretti bid is less attractive to some than it might appear at first sight.
There is also a project known as Panthera Team Asia, which says it is ready to enter the expressions of interest process, but is likely to be some way down the wanted list.
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"Panthera Team Asia" sounds very legitimate.