What's the name of bus. strategies, where a company add branch in a place in order to protect it's customer?

What's the name of bus. strategies, where a company add branch in a place in order to protect it's customer?

For example Company A has a bigger market share and customer than company B.
Company B open in X City. Company A see that to open in X city is not really profitable, but they open it, in order to protect their customer that located in X city to move into B company.

What's the name of the strategy used?
Thanks in advance.

never heard of that - but such an activity would be defensive or protective. I don't want to quibble but don't see how that would count as a strategy - it might be a response or an activity or a tactic but when you think of what strategy is all about - then doing something non profitable for no other reason than to protect yourself is not good business, and is no form of strategy (imho).