Your thought experiment is flawed at many levels. To look at only one aspect - the question is not on the company (bank) but on people. The answer is Yes. Ban

Your thought experiment is flawed at many levels. To look at only one aspect - the question is not on the company (bank) but on people. The answer is Yes. Banks will ban it's employees from buying those pesos because of something called "conflict of interest". It wouldn't matter if the price jumps or not. In fact, a conflict of interest can exist even if there are no improper acts as a result of it. There are no laws against it for cryptocurrencies, yet. But, if something like this happened, it is unfair to Coinbase's customer.