A rule created by the Financial Industry Regulatory Authority (FINRA) to protect individual investors from conflicts of interest that may arise when brokerage firms and mutual funds collaborate.

The main violation the rule is designed to prevent is an arrangement between a brokerage firm and a mutual fund wherein the brokerage firm directs its clients to the mutual fund company (generating sales) and the mutual fund, in turn, sends its trades through the brokerage firm (generating commissions). Brokerage firms and mutual funds can be fined by FINRA (formerly the NASD) if there is proof that they have violated anti-reciprocal rules.