No formal annoncement is required.
That depends of the laws of the country in which the company is registered. As you have not specified this in your question we can not provide you with a precise answer. Please take care to make your questions precise.
No. Tax returns are considered private financial matters and are not made available to others who for some reason think they are entitled to get into your business. Sometimes politicians may release their tax returns but this is a voluntary move on their part and is in no way a requirement for anyone.
WHAT IS SUBJECT
to fulfill the legal requirement
verification of public data is public auditablity
No formal annoncement is required.
Public Announcement was created in 1990.
A Public Disservice Announcement was created in 2009-03.
Public Service Announcement
speech
Public announcement
declaration
Public announcement
It is called a public service message, I believe.
No
A general announcement for no specific person
A general announcement for no specific person