Am I required by law to disclose my license out of state?

[Phil Ting]

Title says it all. I work with two companies. One company I assist in acquisitions all over the midwest. The other company is my employing broker, where I have recently hung my California real estate license. I always disclose when I do real estate locally, but I'm wondering if I need to put my license number on all my business cards and my e-mail signature when I'm doing business in other states. 

I've always disclosed my license number to be safe, but the company I'm working with is rebranding and printing new business cards. I find it odd (and even somewhat confusing) to have my license number written on a business card that doesn't belong to my employing broker.