DSCR Sensitivity Analysis: What If Rates Rise 1%?

Every DSCR deal looks great at the rate you're quoted today. But what happens if rates jump before you lock? What if rents soften? What if property taxes spike? A sensitivity analysis tests your deal against adverse scenarios — because the market doesn't care about your projections.

What Is a Sensitivity Analysis?

A sensitivity analysis changes one variable at a time to see how it affects your key metrics: DSCR ratio, monthly cash flow, and cash-on-cash return. It answers the question: "How much can go wrong before this deal breaks?"

The Three Variables That Matter Most

1. Interest rate — A 1% increase can add $120–$180/month to payments on a $200K loan
2. Rental income — A 10% rent drop (tenant loss, market softening) crushes cash flow
3. Operating expenses — Property tax reassessment, insurance spikes, major repairs

Rate Sensitivity: The Big One

As of early 2026, DSCR loan rates range from 7.0% to 8.5%. But rates fluctuate, and you might not lock for 30–60 days after starting the application.

Impact of a 1% Rate Increase

$250,000 property, 25% down, 30-year fixed:

A full 1% rate increase (7.5% to 8.5%) drops DSCR by 0.09 and adds $131/month to payments. Over 30 years, that's $47,160 in additional interest.

What This Means for Your Deal

If your deal works at a 1.23 DSCR with current rates, ask yourself:

• Does it still qualify if rates jump 0.5% before you lock? (1.18 — yes, with worse pricing)
• Does it still work at +1.0%? (1.14 — yes, but tight)
• At +1.5%? (1.10 — very marginal)

Rule of thumb: If your deal doesn't survive a 1% rate increase, it's too fragile. Negotiate a lower purchase price or find more income.

Rate Lock Strategy

Lock your rate as early as possible to eliminate rate risk:

• 30-day lock: Free at most DSCR lenders
• 45-day lock: Sometimes a small fee (0.125% of loan amount)
• 60-day lock: Standard for DSCR purchases (0.125–0.25%)
• Float-down option: Some lenders allow you to take a lower rate if rates drop after you lock (costs 0.25–0.50% upfront)

Rent Sensitivity

Modeling Rent Declines

What happens if rents drop?

Same $250K property at 7.5%:

A 10% rent decline turns a marginally profitable deal into a $2,652/year loss. A 20% decline drops the DSCR below 1.0 — meaning rental income doesn't even cover the mortgage.

When Do Rents Drop?

• Recession: 2008–2009 saw 3–8% rent declines in most metros
• Oversupply: New construction flooding a market can push rents down 5–15%
• Local economic shock: Major employer leaving, base closure, industry decline
• Seasonal: Some markets see 10–15% drops in off-season (vacation rentals)
• COVID-style disruption: March 2020 saw temporary rent declines of 5–15% in some urban markets

Building Rent Decline Protection

• Underwrite at 25th percentile rents (not median or asking)
• Target deals with DSCR above 1.25 to survive a 10%+ rent decline
• Diversify across markets to avoid single-market risk
• Maintain 6-month reserves per property

Expense Sensitivity

Property Tax Increase

What if property taxes increase 25% (common after reassessment)?

Insurance Increase

What if insurance doubles (happening now in FL, CA)?

Combined Worst Case

What if rates rise 1%, rents drop 5%, taxes increase 25%, AND insurance doubles?

• Rate: 8.5% → P&I: $1,442
• Rent: -5% → $1,995
• Taxes: +25% → $313
• Insurance: +100% → $300
• PITIA: $2,055
• DSCR: 0.97

The deal is underwater in a combined stress scenario. This doesn't mean you shouldn't buy — but you should know your exposure and maintain adequate reserves.

Building Your Sensitivity Table

In a Spreadsheet

Create a two-variable data table:

Rows: Rent scenarios (-20% to +10%) Columns: Rate scenarios (current -0.5% to +1.5%) Cells: DSCR ratio for each combination

Color code: Green (1.25+), Yellow (1.0–1.24), Red (below 1.0)

This gives you a visual map of where your deal breaks.

Key Breakeven Points

Calculate and document:

• Rate breakeven: At what rate does DSCR drop below 1.0?
• Rent breakeven: At what rent does DSCR drop below 1.0?
• Vacancy breakeven: How many months of vacancy can you absorb per year?
• Expense breakeven: How much can total expenses increase before DSCR fails?

The Resilience Score

Rate your deal's resilience on a simple scale:

Strong (Target: All Deals)

• DSCR above 1.25 at current terms
• Survives 1% rate increase (DSCR still above 1.10)
• Survives 10% rent decline (DSCR still above 1.10)
• Survives combined stress (rates +0.5%, rents -5%, expenses +15%)

Adequate (Acceptable with Reserves)

• DSCR 1.15–1.24 at current terms
• Survives 0.5% rate increase
• Survives 5% rent decline
• Breaks at combined stress — need strong reserves

Fragile (Proceed with Caution)

• DSCR 1.00–1.14 at current terms
• Any single adverse change pushes DSCR below 1.0
• Combined stress results in significant negative cash flow
• Only buy if there's a clear value-add or rent-increase path

Unacceptable (Walk Away)

• DSCR below 1.0 at current terms
• Negative cash flow from day one
• No clear path to improvement
• Deal only works with unrealistic assumptions

Frequently Asked Questions

How likely is a 1% rate increase during my DSCR process?

Rates can move 0.25–0.50% in a single month based on treasury yields and market conditions. A 1% swing over a 60-day closing period is uncommon but not impossible. Lock your rate as soon as you can.

Should I skip a deal if it fails the stress test?

Not necessarily. A deal that fails under extreme combined stress but works under individual stresses is normal. Focus on single-variable resilience (can it handle 1% rate increase OR 10% rent decline?) rather than every-bad-thing-at-once scenarios.

How do I stress test a short-term rental DSCR deal?

STR deals need a vacation-to-long-term conversion stress test: what's the DSCR if you have to convert to long-term rental? If the deal still works as a long-term rental, the STR income is pure upside.

What's more dangerous — rate risk or rent risk?

Rate risk is front-loaded (affects you at closing and refinancing). Rent risk is ongoing (affects you every month). Both matter, but rent risk has more long-term impact because you face it every lease cycle.

Should I pay for a float-down option on my DSCR rate lock?

If rates are volatile and you have a 45–60 day closing timeline, a float-down option for 0.25% can be good insurance. If rates drop 0.5%+ during your process, it pays for itself multiple times over.

The Bottom Line

Sensitivity analysis separates professional investors from gamblers. Every deal looks good in the best case — what matters is whether it survives the worst case. Run rate, rent, and expense scenarios on every deal before you make an offer.

The goal isn't to find deals with zero risk — those don't exist. The goal is to understand your risk, quantify it, and make sure your reserves can handle the downside.

Model your DSCR under different scenarios with HonestCasa's tools to see exactly where your deal breaks.