ChipMod took a Nikon D850 camera apart and came to the conclusion that the sensor inside is made by Sony (Google translation):
We had another Nikon D850 sensor teardown last year, but we could not see the actual numbers on the back of the sensor since they were covered by a metal frame. This time ChipMod provided a picture of the back of the sensor where we can clearly see IMX309AQJ and 1183456:
A quick Google search shows us that IMX309AQJ is indeed a Sony made sensor:
Almost all Sony sensors have “IMX” in their model name – see this post for more details.
At the end of the day, it is irrelevant who makes the sensor for the D850, but there have been many speculations on that part in the past and some even suggested that sensor shortage is the reason why the Nikon D850 is still out of stock in the US (I don’t think this is the case).
The rumors about TowerJazz making the D850 sensor started here on NikonRumors a while back and then they took a life of their own. TowerJazz did indicate that they are working with a leading DSLR company on their next-generation sensors, but those sensors are not yet released and it was never confirmed that they were talking about Nikon.
List of Nikon DSLR cameras and their sensor manufacturer/designer can be found here.
TowerJazz working on a new full frame sensors with global shutter
First indication that the Nikon D850 sensor could be made by TowerJazz
Nikon D850 DSLR camera teardown update: the 45.7MP CMOS BSI sensor
List of all Nikon DSLR cameras and their sensor manufacturer/designer
