If your business have enough impact (ie if you were an industry owner in Nazi Germany), you automatically became insider (yes, even Jews for a time).

Small business though, it was better to be friend with small local powers.

I remember reading about one case where a small busines owner's establishment was vandalized because people wrongly thought he was a jew. His reaction was to clear up the perceived misunderstanding by joining the party. It actually turned out to be profitable for him at first because of the connections he made, but, he was also obliged to continue working with them as well. Even when he didn't want to, because he owed his success to party. The whole thing read like a mafia story.

Krystal Nacht being a prime example