Yes, according to an Ethics seminar I attended.  I can't tell you the specific place to find in Circ230.               Was told it was a violation to use information provided by one client to prepare a 1099 for another client.  Meaning ABC company needs to issue 1099 to John Doe.   Company XYZ also needs to issued 1099 to John Doe but doesnt have his info.  I can't use info ABC gave me to complete XYZs 1099.   Crazy!!!