Most likely Jaguar is involved financially and it's not a straight purchase. From Wired:

"Jaguar, for its part, gets a large chunk of guaranteed sales and a chance to look like it’s at the forefront of this emerging technology."

- Waymo Expands Its Robo-Fleet with Electric Jaguar SUVs, https://www.wired.com/story/waymo-buys-jaguar-suvs/