O/F: Owner Finance
OA: Operating Assets
OARS: Opening Automated Report Service

OAS: Option Adjusted Spread
OASDI: Old Age Survivor and Disability Insurance
OASDI: Old Age, Survivors and Disability Insurance
OASDI: Old Age, Survivors and Disability Insurance Program
OATS: Options Automated Trading System
OATS: Order Audit Trail System
OBO: or best offer
OBO: Order Book Official
OBS: Off Balance Sheet
OBSC: Off Balance Sheet Commitment

OBV: On-Balance Volume
OCC: Office of the Comptroller of the Currency
OCC: Option Clearing Corporation
OCC: Options Clearing Corporation
OCCO: Outward Cheque Clearing Outsourcing

OCF: Operating Cash Flow
OCO: One Cancels the Other
OCP: Outstation Cheque Purchase
OCR: Official cash rate
OCT: Order Confirmation Transaction
OD: Overdraft
ODFI: Originating Depository Financial Institution
ODR: Overseas Depository Receipt
OE: Operating Expense

OECD: Organization for Economic Cooperation and Development

OEM: Original Equipment Manufacturer
OER: Operation Expense Ratio
OEX: S&P100 Index
OEX: Standard & Poor's 100 Index
OEX: Symbol for the Standard & Poor's 100 Index
OFAC: Office of Foreign Assets Control
OFC: Offshore Financial Center
OFC: Open Financial Connectivity

OFT: Office of Fair Trading
OGE: Osaka Grain Exchange
OHLC: Open, High, Low, Close
OHLC: Open, High, Low, Close Chart