- Obligation
- Obligor
- Offer in compromise
- Offering
- Office of Comptroller of the Currency
- Office of Federal Housing Enterprise Oversight - OFHEO
- Office of Thrift Supervision
- Offline debit card
- Old Age, Survivors and Disability Insurance Program - OASDI
- On account
- On-the-spot loan
- One year adjustable
- One-year adjustable
- One-Year Constant Maturity Treasury - 1-Year CMT
- One-Year Treasury Constant Maturity
- Online banking
- Online bill payment
- Online debit card
- Open access
- Open house
- Open listing
- Open mortgage
- Open panel
- Open-end credit
- Open-end lease
- Open-end mortgage
- Operating lease
- Option
- Option arm
- Optionally renewable
- Options
- Oral agreement
- Ordinary annuity
- Ordinary dividends
- Ordinary income
- Ordinary interest
- Ordinary shares
- Original principal balance
- Origination
- Origination fee
- Origination points
- OTS
- Outpatient
- Outstanding
- Over-the-limit fee
- Overadvance
- Overcontribution
- Overdraft
- Overdraft annual cost
- Overdraft minimum amount
- Overdraft protection
- Overlay
- Overlying mortgage
- Owe
- Owner financing
6.06
