65As regards, generally, the nature of business secrets or other information covered by the obligation of professional secrecy, it is necessary, first of all, that such business secrets or confidential information be known only to a limited number of persons. Next, it must be information whose disclosure is liable to cause serious harm to the person who has provided it or to third parties (Postbank v Commission, cited in paragraph 63 above, paragraph 87, and see also Commission Notice 2005/C 325/07 on the rules for access to the Commission file in cases pursuant to Articles 81 [EC] and 82 [EC] (OJ 2005 C 325, p. 7), paragraphs 3.2.1 and 3.2.2). Finally, the interests liable to be harmed by disclosure must be worthy of protection. The assessment as to the confidentiality of a piece of information requires, in this regard, the individual legitimate interests opposing disclosure of the information to be weighed against the public interest that the activities of the Community institutions take place as openly as possible (Bank Austria Creditanstalt v Commission, cited in paragraph 46 above, paragraph 71).