Legal Question in Legal Ethics in Pennsylvania

I don't understand your question. Paying taxes has nothing to do with this. If the certificate is owned jointly, how does it read - "pay to A or B" or "pay to A and B"?

It makes a difference. If the wording is "or" then the bank can pay either one of the joint owners. If it is "and" then the bank either pays one-half to each or issues one check which you both have to sign before it can be deposited or cashed.

Is the other joint account holder alive or dead? If dead, then you might be the sole account holder, but from question, I assume they are still alive. If you inherited the cd along with another person and paid more than your fair share of the inheritance taxes, then you in fairness should be reimbursed for the taxes that you paid for the other person and that sum should be deducted from ttheir share.