If I worked for someone 16 years selling a product for a company that “I” built the relationship with them, so far that they made us exclusive dealers, but for different reasons my relationship with my boss is extremely sour … it became so bad that it starts effecting my personal life – bottom line, I have to leave.
Am I allowed to open a showroom a few blocks down and sell for that same company ….they will sell through me regardless because they know me personally and know I sold their product successfully for the past 16 years … as a matter of fact my boss doesn’t even know how to sell this product (it’s a custom line that he doesn’t have any knowledge in)?
Under the circumstances, and if there is no way to resolve the matter with the boss, it is permitted for you to open up and sell for the same company.
The possible problem of opening up and taking the client with you is known as maarofia, which refers to “poaching” a client from somebody else.
The Rashba (3:83; 6:259) writes that if a Jew has a regular client, it is not permitted to “poach” the client away, because the Jew is relies on the custom of his regular client (the idea is derived from the Gemara in Bava Basra concerning somebody who has already laid out a net to catch fish), and it is considered interfering with his income.
This idea is ruled by the Rema (156:5).
However, in the case of the question the reliance of the boss is entirely dependent on the employee who built up and maintained the relationship (and only he can continue to do so), so that once the employee leaves the client “leaves with him” — something the boss realizes or ought to realize.
Therefore, although it remains something worthy of avoiding, if the problems cannot be resolved it is permitted to “take the client” with.