client vs. customer

Hello everyone,

I’d like to ask which word it’s better to use in the following context:

The president of the bank says: “This company is our large client/customer”; client/customer meaning that the bank, for example, opened a credit line for the company or something like that.

The two words are used completely interchangeably in that context, and one is not better than the other. This means you can just flip a coin or throw a dart, or choose the one you personally prefer.

Thank you very much, Jamie (K).