Portfolio Stress Test Calculator

Portfolios need stress tests. This calculator models vacancy, rate, and expense shocks.

Base NOI

Debt service

Vacancy shock

Expense shock

Rate shock (bps)

Variable debt balance

Stressed DSCR

1.13

Stressed NOI

$2,391,200

Additional debt service

$170,000

How the math works

Stressed NOI ≈ (gross rev × (1−vacancy shock)) − (opex × (1+expense shock)). Stressed DSCR = NOI ÷ (debt service + additional interest).

Run this with your current rate cap expiration date on the calendar. A portfolio with a strong base DSCR that goes sub-1.0x on a 200 bps shock is fine today but insolvent the day the cap drops off — size the replacement or extension before it matters.

How to Use

Enter base-case NOI.
Enter debt service.
Enter vacancy shock %.
Enter expense shock %.
Enter rate shock bps on variable debt.
Enter variable debt balance.
Read stressed DSCR.

Frequently Asked Questions

What to stress?

Vacancy (5-15 pts), expenses (10-25%), interest rate on variable debt (100-400 bps), revenue growth (0% vs 3%), cap rate at exit (50-150 bps wider). Stress tests should double the worst year of the last cycle.

DSCR triggers?

Most commercial covenants trip at 1.15-1.20x DSCR. Multifamily agency debt often at 1.25x. Below triggers: cash sweep, forbearance, extension negotiation, or default. Stress-test to identify the exact shock that trips covenants.

What to do with results?

If stressed DSCR < covenant: pre-emptively buy rate caps, pay down variable debt, or negotiate covenant relief now while strong. Running it close is fine in base case but lethal under stress — every refinance window counts.