Short answer：There is no universal reserve percentage. Estimate the cash gaps caused by interrupted income, vacancy or major repairs, then decide how much accessible money to retain.
Separate recurring and one-off costs
Keep mortgage payments, living expenses, management and insurance separate from dated repair levies, tax and moving bills. A hypothetical HK$20,000 monthly shortfall for six months requires HK$120,000 for that shortfall alone; six months is an assumption, not a universal recommendation.
Check accessibility
Do not count an unsold property, unapproved credit or a tenant’s deposit as freely available reserves. List withdrawal delays and penalties. Test income concentration and simultaneous lease expiries separately.
Before deciding
- List known upcoming bills
- Compare occupied and vacant cash flows
- Plan how depleted reserves would be rebuilt
Sources and method
Sources support the specific rules described. Checklists and hypothetical calculations are editorial explanations, not measured market results or individual approvals.
Revision：Removed unsupported experience, case outcomes and statistics; corrected the topic-specific rules and limitations described above.
Scope：General information only, not personalised legal, tax, immigration, admissions or investment advice.