Interest reserves on bridge and construction loans, explained

An interest reserve is money set aside from the loan at closing to pay the loan's interest for a set period. Instead of the borrower making monthly interest payments out of pocket, the lender or servicer pays them from the reserve. Interest reserves are common on construction and heavy renovation loans, where the property produces little or no income until the work is finished.

This guide explains how interest reserves work, how they're sized, what they do to the numbers, and what lenders and capital partners should watch.

Why interest reserves exist

During construction or a major renovation, a property often can't be rented and can't generate income. The borrower is also spending cash on the project. An interest reserve means:

• The borrower doesn't have to fund monthly interest from other sources during the build.
• The lender gets paid on schedule, with less risk of payment defaults caused by cash flow timing rather than a failing project.

The trade-off is that the borrower is borrowing the money to pay the interest, so the loan balance is higher and the reserve itself accrues interest once it's drawn.

How an interest reserve works

1. At closing, part of the loan amount is set aside in a reserve account (or held back by the lender) rather than given to the borrower.
2. Each month, the servicer pays that month's interest from the reserve.
3. The amount drawn is added to the outstanding balance, if it isn't already counted as funded.
4. When the reserve runs out, or the reserve period ends, the borrower starts paying interest from their own funds.

The mechanics depend on whether the loan is fully funded at closing or interest charged on drawn balances only ("Dutch" vs. "non-Dutch" interest). On a loan where interest is charged only on the money actually drawn, interest grows as construction draws are released, and the reserve needs to cover that rising amount.

Sizing the reserve

A reserve is typically sized to cover interest for the expected construction or stabilization period, often with some cushion. The calculation depends on how the loan is drawn.

Worked example: interest on drawn balance

Hypothetical figures, for illustration only.

A renovation loan has:

• $300,000 advanced at closing for the purchase
• $150,000 construction holdback, released in three equal draws at the end of months 2, 4 and 6
• 10% annual interest rate, interest-only, charged on the drawn balance
• An expected 9-month project

Monthly interest is roughly balance × 10% ÷ 12.

Months	Drawn balance	Monthly interest	Months	Interest for the period
1–2	$300,000	$2,500	2	$5,000
3–4	$350,000	$2,917	2	$5,833
5–6	$400,000	$3,333	2	$6,667
7–9	$450,000	$3,750	3	$11,250
Total			9	$28,750

A reserve of about $29,000 would cover the expected project, ignoring interest on the reserve itself. Many lenders would add a cushion for delays. If the project runs three months late at the full balance, another $11,250 would be needed.

That's the central point: the reserve is only as good as the schedule it's based on.

What a reserve does to the numbers

Because the reserve is part of the loan, it affects leverage:

• Loan-to-cost. Many lenders include the reserve in total project cost, so it's financed alongside the purchase and renovation.
• Loan-to-value. The reserve increases the loan amount, which increases LTV and loan-to-ARV.
• Borrower cash. A financed reserve reduces how much cash the borrower must bring for carrying costs, but it doesn't reduce their required equity unless the lender allows it.

In the example, the total loan with the reserve is about $479,000. If the after-repair value is $700,000, the loan-to-ARV is about 68% with the reserve, versus about 64% without. See LTV vs. LTC vs. ARV for how each ratio is calculated.

Benefits and risks

	Benefit	Risk
Borrower	Doesn't need cash for interest during the build	Higher loan balance and total interest cost
Lender	Regular payments; fewer cash-flow defaults	Can hide a struggling project, since payments keep arriving
Capital partner	Predictable income during construction	Reserve may run out before the project finishes

The biggest risk is masking. Because interest is paid automatically, a project that's behind schedule can look like a performing loan until the reserve is gone. By then, the borrower may be out of cash too.

How lenders manage reserve risk

• Size the reserve to a realistic schedule, with a cushion for delays.
• Monitor construction progress, not just payments. Draw inspections show whether the project is on track. See construction draw management.
• Test the reserve in the in-balance check. If the remaining reserve won't cover interest through completion, treat it like a budget shortfall that the borrower must fund.
• Set clear rules for what happens when the reserve runs out: borrower pays monthly, or a default is triggered.
• Report reserve balances to the loan's owner alongside draw activity.

What capital partners should check

When funding a loan with an interest reserve, look for:

• How the reserve was sized: the assumed schedule, rate and draw timing.
• Whether interest is charged on the full commitment or drawn balance.
• Who controls the reserve and how it's reported.
• What happens when it's depleted, and whether the borrower has the cash to pay after that.
• Project progress: a reserve paying interest on a stalled project is a warning sign, not reassurance.

Key takeaways

• An interest reserve sets aside part of the loan to pay interest during construction or stabilization.
• It's sized to the expected schedule and draw timing, so delays can exhaust it early.
• Reserves increase the loan balance and leverage, which should be reflected in LTV and LTC.
• The main risk is that automatic payments mask a project in trouble; monitor progress, not just payments.

How Lender Capital fits

Construction and renovation loans placed through Lender Capital come with the budget, draw schedule and loan terms, including any interest reserve, so capital partners can see how the loan is structured before committing. Lenders get capital for larger projects, and one capital partner funds the whole loan.

See how it works for lenders or for capital partners.