Definition
A downside case is a conservative underwriting scenario that assumes performance is worse than expected or market conditions become less favorable. Investors use it to stress-test cash flow, debt coverage, and exit value — and to understand how much “room for error†a deal has before capital is impaired.
What a Downside Case Tests
A good downside case doesn’t assume everything breaks at once — it targets the risks that matter most for the specific deal (lease-up risk, expense volatility, rate risk, exit liquidity, capex surprises, etc.).
Common downside adjustments
- Lower revenue: slower rent growth, higher vacancy, higher concessions, higher bad debt, weaker other income.
- Higher expenses: faster growth in taxes/insurance/utilities, more repairs and turnover, payroll pressure.
- More capex: cost overruns, deeper deferred maintenance, higher replacement reserves.
- Slower business plan: delayed renovations, slower lease-up, lower renewal conversions.
- Tighter debt conditions: higher interest rate, less proceeds, reduced IO, tougher refi terms.
- Worse exit: higher exit cap rate, higher selling costs, longer marketing period.
Why It Matters
The downside case is about capital preservation. If a deal only meets targets in the base or upside case but fails quickly under reasonable stress, the investment may be too fragile for the risk taken. Downside analysis helps investors set a margin of safety and avoid paying for outcomes they can’t control.
Investor Uses
- Risk screening: eliminate deals with weak resilience or high probability of permanent loss.
- Debt sizing: test DSCR and debt yield under stressed NOI and higher rates.
- Liquidity planning: estimate how much cash reserve is needed to survive a rough period.
- Pricing discipline: decide the max price you can pay while still surviving downside outcomes.
- Negotiation leverage: justify retrades or pricing reductions based on identifiable risk factors.
Example
An investor underwrites a value-add multifamily deal with a base case of 94% stabilized occupancy and 3% annual rent growth. In the downside case they assume:
- Occupancy: 90% (lease-up takes longer)
- Rent growth: 1% (demand softens)
- Concessions: 1 month free for new leases during year 1
- Expenses: +6% taxes/insurance (non-controllable spike)
- Exit cap rate: +75 bps vs. the base case
The investor then checks whether the property still covers debt service, whether cash flow turns negative, and whether exit proceeds can repay the loan with acceptable equity value remaining.
Common Pitfalls
- Token downside: making changes too small to be meaningful (a “downside case†that is still optimistic).
- Stacking unrealistic shocks: assuming every variable fails simultaneously without a rationale.
- Ignoring non-controllables: failing to stress taxes, insurance, and utilities.
- Not stress-testing the exit: focusing on operations but assuming a friendly cap rate at sale.
- Forgetting timing: cash flow can fail from when problems occur, not only how large they are.