The definition I inferred from the word flexfield qualifier is “which segment qualifies for which attribute“. Each Segment can have one of the following Qualifying attributes attached to it. Some of them are mandatory others are optional. Cost Center: Usually assigned to Department Segment. This qualifying segment is used by Oracle Assets. Natural Account: This qualifier when attached to a segment enables the five nature of accounts Asset, Liability, Expense,Revenue, Owner’s Equity. It also assigns the option of Reconciliation account and Third Party Control. Balancing: This qualifier is usually assigned to the segment on which the Balance Sheet is required. System balances the Debit and Credit of the ledger on this segment. Intercompany: This qualifier is used to identify the transaction between two entities under one group. More on this in Intercompany. Management: This qualifier is used as an additional control on Data Access Set. Secondary Tracking: To be discussed Flexfield Qualifiers determines the nature of the segment. If you define a COA structure as Company-Department-Account How will the system knows which segment is natural account? Which segment should be used to balance the accounting entries? which segment will be used as Cost Centre in Fixed Assets? It is the qualifier through which the system assign particular attribute to the segment. If I attach Natural Account qualifier to Company Segment, the system will not validate anything against this assignment. It will simply enable the five natures of accounts and treat the Company segment as Natural Account. So for particular segment, a particular qualifier is assigned. This is the one time activity and freezes as we freeze the COA Structure.