We have a business savings account and the authorized signer has been coming in to withdraw large sums by cash. CTRs have been filed when appropriate. Our tellers have been giving them cash as opposed to a bank check payable to the business (it is incorporated). We are having the discussion on whether or not we should be giving business customers only bank checks and not cash. On a deposit we will not allow them to have cash back, but deposit an entire check. However, if the person has a company check signed by an authorized signature we will cash the check.

Is there any law/regulation/requirement that says you should not give cash to a business customer from a savings withdrawal?

No, there is no law that stipulates that. As long as this person is an authorized signer I don't think you can refuse his request unless you invoke the 7 day wait.

You also better check your corporate resolution from the customer. You want to make sure that the corporate resolution specifically allows the withdrawal of cash in this manner. Especially if this may be a possible embezzlement situation.