Nikon D850 sensor confirmed as Sony-made

It can be interesting, for the more tech-inclined photographer, to speculate about where camera makers are getting their sensors from. However, to be truly certain, you'd need to tear the camera apart and see what's printed around the edge of the chip.
ChipMod - a camera modification company - has done just that, and has posted its findings on the AstroCN forum, showing that the D850's sensor has a Sony product code stamped on the back of it.
This will come as no surprise to anyone who's been curious about the issue: DPReview forum user Bobn2 (a computer science professor whose areas of expertise include imaging) pointed out immediately that all the published images of the chip showed a wiring pattern consistent with previous Sony designs. The sensor's performance then revealed it to have a dual-gain design that's been a feature of recent Sony chips (something we believe was licensed from Aptina, making Sony one of the only companies able to offer it).
However, claims by Israeli chipmaker TowerJazz that it supplies to "a DSLR manufacturer" were taken by some to be evidence that it was the source of this chip. We still don't know which company TowerJazz was referring to, nor how precisely it were using the term 'DSLR.'
What's interesting, though, is that this news confirms what Sony told us about the way its semiconductor company deals with external clients: other companies can commission Sony Semiconductor to make them a sensor and can include their own intellectual property in the design, without that information (or the rights to use it) being available to Sony's camera division. Hence the D850 features the BSI and dual gain designs that Sony uses in many of its own cameras but is also able to provide an ISO 64 mode that allows the Nikon to rival some of the latest medium format cameras, but that Sony cameras don't offer.

This would also help explain how Nikon justifies its statements that the sensor is "designed by Nikon."