The Sarbanes-Oxley Act: Overview and Implementation Procedures Manual

ANALYST PROTECTIONS The Commission, or upon the authorization and direction of the Commission, a registered securities association or national securities exchange, shall have adopted, not later than 1 year after the date of enactment of this section, rules reasonably designed to address conflicts of interest that can arise when securities analysts recommend equity securities in research reports and public appearances, in order to improve the objectivity of research and provide investors with more useful and reliable information.
Essentially there should be no relationship between the broker and the company that may be perceived as a conflict of interest. No debts or financial interest other than the normal brokerage commissions.