(a) An employee is prohibited for one year from the date of entry on duty with the Corporation from participating in a particular matter when an employer, or the successor to the employer, for whom the employee worked at any time during the one year preceding the employee's entrance on duty is a party or represents a party to the matter.

(b) For purposes of this section, the term employer means a person with whom the employee served as officer, director, trustee, general partner, agent, attorney, accountant, consultant, contractor, or employee.

(c) The one-year prohibition imposed by paragraph (a) of this section, and the one-year period preceding the employee's entrance on duty specified in paragraph (a) of this section, may each be extended in an individual case based on a written determination by the agency designee that, under the particular circumstances, the employee's participation in the particular matter would cause a reasonable person with knowledge of the facts to question his or her impartiality.