42 C.F.R. § 67.103
(c) Composition of peer review groups. The peer review groups shall be composed of individuals, in accordance with section 922(c) of the PHS Act, as amended, who by virtue of their training or experience are eminently qualified to carry out the duties of such a peer review group. Officers and employees of the United States may not constitute more than 25 percent of the membership of any such group. Members of the peer review group will be selected based upon their training or experience in relevant scientific and technical fields, taking into account, among other factors:
(e) Conflict of interest.
(2) In addition to any restrictions referenced under paragraph (e)(1) of this section:
(i) No member of a peer review group may participate in or be present during any review by such group of a contract proposal in which, to the member's knowledge, any of the following has a financial interest: