OCO order
Order combination in which the execution of one order automatically deletes the other.
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Stock Market Glossary - Letter O
14 terms beginning with "O"
Explore more than 400 curated terms for investors, traders and long-term savers. Detailed definitions, practical context and no marketing jargon — from your first ETF savings plan to option strategies.
Updated: September 11, 2026
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O Terms beginning with O
Open interest
Number of open options or futures contracts that have not yet been closed out.
Learn more →Open-End Fund
Open-ended fund whose shares can be issued or redeemed at any time.
Learn more →Opening Range
Price range of the first minutes of trading as a reference for intraday trades.
Learn more →Opex
Operating Expenditures – ongoing operating costs of a company.
Learn more →option
Right (not obligation) to buy or sell an underlying asset at a set price.
Learn more →Option Greeks
Key figures that measure the sensitivity of an option to price, time and volatility.
Learn more →Order
An order to the broker to buy or sell a security.
Learn more →Order book
List of all open buy and sell orders for a security.
Learn more →Order Flow
Real-time analysis of incoming buy and sell orders.
Learn more →OTC trading
Over-the-counter trading directly between two parties.
Learn more →Outperformance
Better performance than a benchmark.
Learn more →Overconfidence
Behavioral bias in which investors overestimate their skills and information.
Learn more →Overnight deposit
Bank deposit with daily availability and a variable interest rate.
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