(Measure passed House, amended) Freedom of Information Act Amendments of 1986 - Amends the Freedom of Information Act to require agencies to promulgate regulations with regard to the procedures for: (1) designating certain business information confidential; and (2) handling requests for such confidential information. Establishes guidelines for procedures to be followed when an agency is required to notify a submitter that a request has been made for information designated (or treated) as exempt by the submitter. Describes circumstances in which an agency is not required to notify a submitter. Provides for de novo judicial review by a U.S. district court of an agency decision to withhold or disclose records. Directs the court to assess attorney's fees against a submitter where the submitter's reasons for withholding information were not substantially justified.