Paulo,
I wondered too and googled, found this:
https://www.google.com/search?q=zeiss+batis+tamron&ie=utf-8&oe=utf-8
Basically Rumours, yet It was never a secret that some of the earlier Zeiss lenses were manufactured by Cosina was it ? , in the same factory that made those yummy Voigtländer 125 and 180 lenses. I personally couldn't care less as long as the quality is up to Zeiss' standards.
BR Sander
I was being sarcastic on my previous post, as I get tired of this childless drivel about who makes what. For many years now almost all ZEISS lenses (that is the correct name of the company BTW, with capitals), with the exception of cine lenses and other exotic glass (ZE/ZF/Milvus 15 f2.8 comes to mind) have been made by Cosina in Japan. Cosina also makes the Voigtlander lenses.
If ZEISS chose to make the Batis 85 on a Tamron factory, I am sure they had good reasons; maybe the image stabilization lens group was assembled there, I don't care. It still feels like a very good lens. And Tamron have always made some very good lenses, and some even better now, like the recent 35 f1.8 and 45 1.8.
I wonder if the other poster above, who made the childish comment, also thinks his jeans are still made in the USA...