Hello all!

I have a sneaky feeling that I am muddling my German and English, but do I say

1) the company specialises in ...


2) the company specialises on ...


I suspect 1) but can't shake off the doubt.

Half-German lass
It seems your instinct is right...

specialize or specialise /spDGB'laNz/
verb (specialized, specializing)
1 (also specialize in something)
a to be or become an expert in a particular activity, field of study, etc;
b to devote a lot of time, effort, etc (to a particular activity) o He specializes in giving everyone a hard time.
2 said of an organism, body part, etc: to adapt or become adapted for a specified purpose or to particular surroundings.
specialization noun.
specializer noun.
[17c: from special.]
Yes, it's "specialize in"