From ACT Wiki
The desirable qualities of predictability and confidence about future market conditions.
2. Pensions funding.
A pensions funding method is considered stable if it is not greatly affected by fluctuations in experience.
3. Bank funding.
Sources of bank funding are considered stable if they can be depended on to remain as part of the bank's funding, including under conditions of stress.
For example, deposits by retail customers within the size limits of relevant deposit guarantee schemes are considered relatively more stable, compared with larger and professionally managed deposits.