This I did not know – from a Pioneer Press short Q&A article (my editing):
My company has a new district manager. He and I got off to a bad start when he divulged my salary in a mass e-mail and caused an uproar among my new co-workers. Some of them do the same job as me but make considerably less. When I called him on this, he responded, “What’s the big deal? They all tell each other anyway.”
A: Even though the manager showed poor judgment, he didn’t break the law, according to Richard Kass, a partner at Bond, Schoeneck & King in Manhattan. “Employees have no right to privacy in their salaries,” Kass said. The manager may have “acted stupidly,” he said, but he did not break any laws.
To take it one step further:
Your situation is unusual and is the inverse of a situation that actually is illegal. Companies typically get into trouble for directing employees to keep their salaries secret and then trying to punish those who exchange salary information, Kass said.
I’m a bit surprised by that fact. It may be legal, but the manager sharing that information sure seems like a morale-killer. He may have unwittingly opened a Pandora’s box.