Visa Credit Card Account Information Compromised

My Credit Union (American 1st CU--La Habra, CA) recently notified me that my Visa Credit Card account information had been compromised. While I did not have any fraudulent charges on my account, my CU issued a new Visa Credit Card/account to me. My complaint is... neither Visa, nor my Credit Union will disclose who the Merchant is that compromised my information.

I feel, that if someone has my account information, I should know who they are.