quattro[Moderator]
19895
Audemars Piguet & Cartier
So, here's how it all started.
While doing some research on Instagram, I came across the first watch below: an Audemars Piguet Tank with a dial signed "Audemars, Piguet" at 12 o'clock and "Cartier" at 6 o'clock.
It led me to start looking for all the double-signed Audemars Piguet & Cartier watches I could find.
A/ AUDEMARS PIGUET WATCHES WITH DOUBLE SIGNATURE: AUDEMARS PIGUET & CARTIER
These watches were made by Audemars Piguet for their own brand, but retailed by Cartier.
1/ Tank ref. 5839
Case material: platinum (?)
credit: @tomohiro_tomoe_real
2/ Square Yellow Gold

credit: Christie’s
3/ Rectangular platinum
credit: Monaco Legend Group
4/ Round yellow (?) gold
This one belongs to our dear Roni Madhvani
credit: Roni Madhvani
5/ Another round example (gold ?)
credit: Tango1 on WatchCrunch
6/ Disco Volante
credit: Classic 55
7/ Round example with even Arabic numerals
credit: Freeman's
8/ Eight different examples sold by Antiquorum (the research page can
be found here)
credit: Antiquorum
9/ Skeleton example with double signature on the case back
credit: Tajan
During my research I also discovered several pieces signed by Cartier only, but featuring a movement, a case, etc., entirely made by Audemars Piguet.
These watches were, as far as I've understood, made by Audemars Piguet for Cartier.
Let's have a look.
B/ WATCHES MADE BY AUDEMARS PIGUET FOR CARTIER WITH CARTIER SIGNATURE ONLY
First, here are three examples presented on
John Goldberger aka
Auro Montanari's arm !
credit: @goldberger
Let's see them
one by one.
1/ Magnum Tank with triple calendar and moon phase
credit: @cosimo.ardovini, Monaco Legend Group & Craft & Tailord
2/ Ref. 5513 in yellow gold
credit: @goldberger & Artcurial
3/ Square Triple Calendar
credit: @goldberger
4/ Another square Triple calendar with stick indexes instead of Roman numerals
credit: Le Monde Edmond
Now, let's see a
few other examples.
5/ Yellow Gold Chronograph
credit: Monaco Legend Group
6/ White gold Jump Hour
credit: Monaco Legend Group
7/ White gold Ellipse 


credit: Monaco Legend Group 8/ Rose gold Tank
credit: Monaco Legend Group
9/ White gold Tank
credit: Loupe This
10/ Pink Gold Tank
credit: @robinmann
As a final note, I would like to clarify that I decided to post this thread on the
Audemars Piguet forum (not in Horological meandering) because all these watches were
created and manufactured by Audemars Piguet, even if they were
retailed by
Cartier or made
for Cartier.
Thanks for reading.
Best, Emmanuel