- Objective (mutual funds)
- Odd Lot
- Odd Lot Dealer
- Off-Balance-Sheet Financing
- Offensive Competitive Strategy
- Offer
- Offer Price
- Offering Memorandum
- Official Reserves
- Official Statement
- Official Unrequited Transfers
- Offset
- Offset Mortgage
- Offshore Finance Subsidiary
- Old-line Factoring
- Omnibus Account
- On the Run
- On the Run Treasury Yield Curve
- One Man Picture
- One-Factor APT
- One-Way Market
- OPEC (Organization of Petroleum Exporting Countries)
- Open Account
- Open Interest
- Open Book
- Open Contracts
- Open Interest
- Open Listing
- Open (Good-Till-Cancelled) Order
- Open Position
- Open Repo
- Open-End Fund
- Open End Lease
- Open-End Mortgage
- Open-Market Operation
- Open-Market Purchase Operation
- Open-Outcry
- Opening, The
- Opening Bell
- Opening Price
- Opening Purchase
- Opening Sale
- Operating Cash Flow
- Operating Cash Flow Ratio
- Operating Cycle
- Operating Exposure
- Operating Profit Margin
- Operating Lease
- Operating Leverage
- Operating Margin
- Operating Risk
- Operationally Efficient Market
- Opinion of Title
- Opinion Shopping
- Opportunity Cost of Capital
- Opportunity Costs
- Opportunity Set
- Opt Out Plan
- Optimal Contract
- Optimal Portfolio
- Optional Redemption Provision
- Optimization Approach to Indexing
- Optimized Portfolio as Listed Securities
- Option Elasticity
- Option Not to Deliver
- Option Premium
- Option Price
- Option Pricing Theory
- Option Seller
- Option Writer
- Option-Adjusted Spread (OAS)
- Options Contract
- Options Contract Multiple
- Options on Futures
- Options on Physicals
- Organized Exchange
- Original Face Value
- Original Issue Discount Debt (OID Debt)
- Origination Fee
- Original Margin
- Original Maturity
- Origination
- OTC
- OTC Options
- Other Capital
- Other Current Assets
- Other Long Term Liabilities
- Other Sources
- Out-of-the-Money Option
- Out Trade
- Outright Rate
- Outsourcing
- Outstanding Share Capital
- Outstanding Shares
- Outward Arbitrage
- Overbought/Oversold Indicator
- Overfunded Pension Plan
- Overlapping
- Overlay Strategy
- Overnight Delivery Risk
- Overnight Repo
- Overperform
- Overreaction Hypothesis
- Overseas Private Investment Corporation (OPIC)
- Overshooting
- Oversubscribed Issue
- Oversubscription Privilege
- Over-the-Counter Market (OTC)
- Overwriting
- Oversubscribed Issue
- Oversubscription Privilege