For many people in the US, the cell phone number is almost as permanent as their Social Security Number (SSN). Consumers find changing their number to be a super hassle. However, business and rooks have caught onto the permanence of these numbers, and that makes it a problem.
As the New York Times notes today, SSNs are regulated and disclosure without permission is a violation of Federal privacy law.Companies have to go to great pains to protect these numbers, and even then, fail to do so.
There is no similar regulation for cell phone numbers. Companies have started using them as identification numbers for consumers and to link data from different sources. For consumers, that has trouble written all over it. Even more so if you use your phone for purchases in stores or online.
I don’t know of any expert in payment security who uses the cell phone for banking or purchase transactions.
Be careful about who knows your cell phone number!