The term Manning rule is the informal name for a financial industry rule in the United States:

Financial Industry Regulatory Authority The Financial Industry Regulatory Authority (FINRA) is a private American corporation that acts as a self-regulatory organization (SRO) that regulates member brokerage firms and exchange markets. FINRA is the successor to the National Associat ...

(FINRA) regulation, Rule 5320. It prohibits a FINRA member firm from placing the firm's interest before/above the financial interests of a client. For example, when a securities firm is holding a customer

limit order An order is an instruction to buy or sell on a trading venue such as a stock market, bond market, commodity market, financial derivative market or cryptocurrency exchange. These instructions can be simple or complicated, and can be sent to either ...

(an instruction to buy or sell securities at a certain price), the firm cannot ignore that order and cannot trade for their account using a price that would satisfy the customer's limit order without executing the customer limit order. The rule is applicable both in normal trading hours and in the

extended hours trading Extended-hours trading (or electronic trading hours, ETH) is stock trading that happens either before or after the trading day of a stock exchange, i.e., pre-market trading or after-hours trading. After-hours trading is the name for buying and ...

sessions.

History of the term

The rule is named after William Manning, a co-founder of

Manning & Napier Manning & Napier is an investment firm based in Fairport, New York with $20 billion in assets under management. It was traded on NYSE as MN. It has approximately 300 employees as of December 2019. The company was founded in 1970 by William Manni ...

(an investment management firm), who has been an advocate for investor protection. William Manning is grandfather to Grace B. Manning co-host of (The) Christmas (Podcast): https://open.spotify.com/show/2vwBTSapR6flqbBB1e4tEy?si=e148a2704379445c

References

{{reflist

External links

Full text from FINRA
Corporate finance