Interest-Only vs. Amortization: Which Structure Works for LATAM Operators
When infrastructure operators secure financing, the interest rate gets all the attention. But the repayment structure, how you pay back the capital, often has a bigger impact on your business than the rate itself.
This post compares two structures through worked examples, using real LATAM market rates. Bookmark it. You'll need it.
The Two Structures
Amortizing Loan
Equal monthly payments that include both interest and principal. Each month, a portion of your payment reduces the outstanding balance. By the end of the term, you owe nothing.
Interest-Only (Bullet)
Monthly payments cover only the interest. The full principal is returned at maturity as a single "bullet" payment. During the loan term, your outstanding balance never decreases.
Worked Example 1: Peru, SaaS Platform, $500K, 5 Years
Rate: 11.5% (DOB indicative for Peru, score 4)
Amortizing Structure
| Metric | Value |
|---|---|
| Monthly payment | $10,977 |
| Year 1 total payments | $131,724 |
| Year 1 principal repaid | $78,724 |
| Year 1 interest paid | $53,000 |
| Total interest over 5 years | $158,641 |
| Total cost (principal + interest) | $658,641 |
Interest-Only Structure
| Metric | Value |
|---|---|
| Monthly payment | $4,792 |
| Year 1 total payments | $57,500 |
| Year 1 principal repaid | $0 |
| Year 1 interest paid | $57,500 |
| Total interest over 5 years | $287,500 |
| Total cost (principal + interest) | $787,500 |
| Balloon payment at maturity | $500,000 |
The Comparison
| Metric | Amortizing | Interest-Only | Difference |
|---|---|---|---|
| Monthly payment | $10,977 | $4,792 | -$6,185/mo |
| Year 1 cash drain | $131,724 | $57,500 | -$74,224 |
| Total interest | $158,641 | $287,500 | +$128,859 |
| Capital available Year 1 | $0 extra | $74,224 extra | , |
The interest-only operator keeps $74,224 more in the business during Year 1. Over the 5-year term, they pay $128,859 more in total interest. The question is: what's that $74K worth to your business?
Worked Example 2: Colombia, Energy, $1M, 7 Years
Rate: 16.5% (DOB indicative for Colombia, score 4)
Amortizing Structure
| Metric | Value |
|---|---|
| Monthly payment | $20,438 |
| Year 1 total payments | $245,256 |
| Total interest over 7 years | $716,789 |
Interest-Only Structure
| Metric | Value |
|---|---|
| Monthly payment | $13,750 |
| Year 1 total payments | $165,000 |
| Total interest over 7 years | $1,155,000 |
| Balloon payment at maturity | $1,000,000 |
The Comparison
| Metric | Amortizing | Interest-Only | Difference |
|---|---|---|---|
| Monthly payment | $20,438 | $13,750 | -$6,688/mo |
| Year 1 cash retained | $0 extra | $80,256 extra | , |
| Total interest | $716,789 | $1,155,000 | +$438,211 |
At higher rates and longer terms, the total interest difference is larger. But so is the monthly cash flow benefit.
Worked Example 3: Brazil, Data Center, $2M, 3 Years
Rate: 19.75% (DOB indicative for Brazil, score 4)
Amortizing Structure
| Metric | Value |
|---|---|
| Monthly payment | $74,254 |
| Year 1 total payments | $891,048 |
| Total interest over 3 years | $673,133 |
Interest-Only Structure
| Metric | Value |
|---|---|
| Monthly payment | $32,917 |
| Year 1 total payments | $395,000 |
| Total interest over 3 years | $1,185,000 |
| Balloon payment at maturity | $2,000,000 |
For a short-term, high-rate loan, the monthly payment difference is dramatic: $41,337/month. That's capital the operator can deploy into expanding the data center's capacity, which generates more revenue to cover the balloon payment at maturity.
When Interest-Only Makes Sense
Growing assets. If your asset's revenue will increase over the term (expanding capacity, adding customers, new contracts), the lower monthly burden in early years lets you reinvest.
Contractual cash flows. If you have a PPA, SLA, or service contract that guarantees revenue through maturity, the balloon payment is covered by the asset's terminal value or refinancing capacity.
Bridge financing. If you need capital now but expect a larger financing round (or asset sale) within the term, interest-only minimizes your carrying cost until the exit event.
Cash flow seasonality. Operators with seasonal revenue (agriculture, tourism-adjacent infrastructure) benefit from lower fixed monthly obligations.
When Amortization Makes Sense
Declining assets. If your asset depreciates faster than it generates revenue (some vehicle fleets, older equipment), you want principal reduction matching the depreciation schedule.
No refinancing plan. If you can't or don't want to refinance the balloon payment at maturity, amortization ensures you end the term debt-free.
Risk aversion. Some operators prefer the certainty of decreasing debt over the flexibility of lower payments. Both are valid preferences.
The Hybrid: Grace Period + Amortization
Some structures combine both approaches:
- Year 1-2: Interest-only (grace period)
- Year 3-5: Amortization of the full principal
This gives operators breathing room during the ramp-up phase while still eliminating the balloon payment risk. The total interest falls between pure interest-only and pure amortization.
The Real Comparison: Bank Amortizing vs. DOB Interest-Only
For most LATAM operators, the realistic choice isn't between amortizing and interest-only at the same rate. It's between:
- Bank amortizing at 20% (if you can even get approved)
- DOB interest-only at 11.5%
Let's compare for Peru, $500K, 5 years:
| Metric | Bank (20%, amortizing) | DOB (11.5%, interest-only) |
|---|---|---|
| Monthly payment | $13,247 | $4,792 |
| Year 1 cash drain | $158,960 | $57,500 |
| Total interest | $294,786 | $287,500 |
| Monthly savings | , | $8,455/mo |
The DOB interest-only structure is cheaper per month ($8,455 less) and pays roughly the same total interest over 5 years, despite being a "more expensive" structure on paper.
This is the comparison that matters in practice: not theoretical rate vs. rate, but actual monthly impact on the operator's business.
Key Takeaway
The repayment structure isn't just a financial detail; it's a business strategy. Interest-only preserves cash flow for growth. Amortization builds equity. The right choice depends on your asset's trajectory, your refinancing plans, and your risk tolerance.
For most infrastructure operators in LATAM, where assets are growing, contracts are long-term, and cash flow in early years is precious, interest-only is the structure that matches reality.
All calculations use simple interest-only (annual rate / 12 for monthly payments) and standard amortization formulas. Rates referenced are from DOB Capital's rate engine v4.4 for score-4 profiles. Actual rates vary by risk profile, asset type, and jurisdiction.
