Is it? I don't think there is any law that says an employer can't just publish your salary data, which would imply it is their data. And in some cases they are required to share it, such as with the IRS, SEC, social services, state IRS, child support, (Edit: this might be wrong -- and in some states they are even required to share it as part of a reference request).
It of course would not be a smart way to retain employees giving the data out willy nilly, but the law seems to say that it is the employers data to do what they want.
> and in some states they are even required to share it as part of a reference request.
Whoa, hold on. Is that really true? I found this list of states which have banned asking for salary data as part of a job application, but are there states where you're required to share it with a company just because they've asked on the application and are requesting it for verification?
I honestly don't know. I've been told that by HR folks that I know but never looked into it since I'm in California and it's illegal here. It's possible that it is bad information. I'll update my comment and remove it since neither of us can verify it.