• Occupy Wall Street (OWS)
• Offer
• OHLC
• OHLCV
• Omani Rial OMR
• One Cancels Other OCO
• One Time Framing OTF
• On-The-Run Treasuries (OTR)
• Open
• Open Auction In-Range OAIR
• Open Auction Out-of-Range (OAOOR)
• Open Drive OD
• Open Interest
• Open Rejection Reverse ORR
• Open Test Drive OTD
• Opening Range Breakout ORB
• Opening Range Breakout Preference ORBP
• Opening Swing (OS)
• Other Peoples Money OPM
• Othernet
• Out Of The Money (OTM)
• Outside Day OD
• Outside Vertical Bar OVB
• Over The Counter OTC