OECD Secretary-General Mathias Cormann stands to have made substantial gains from secretive share dealings with the man who was CEO of PwC Australia for the entire tax leaks affair.

Former Australian Finance Minister Mathias Cormann — now the boss of the OECD — went to work for the former CEO of PwC Australia almost immediately after leaving office.

The private company of former PwC CEO Luke Sayers is being awarded millions in new Federal Government contracts.