Revolver and Debt Schedule Modeling: Cash Sweep Guide

Introduction

The debt schedule is where more modeling tests go to die than any other tab. Candidates who can build a clean three-statement model and a tidy DCF freeze the moment a revolver, a cash sweep, and a circular interest calculation land on the same page. The mechanics are not conceptually hard, but they are unforgiving: one sign error in the sweep, one balance pointed at the wrong period, and the whole model lights up with circular warnings or spits out $0 of cash forever.

This post walks through the debt schedule the way an interviewer expects you to build it and talk about it. We cover where the schedule sits inside a three-statement or LBO model, the tranche waterfall from revolver down to mezzanine, the difference between mandatory amortization and optional prepayment, how the cash sweep actually works with real sweep percentages, the revolver draw and paydown formula worked through with small numbers, minimum cash balances, a quick word on PIK toggles, and the circularity that makes models blow up along with how to fix it under time pressure. By the end you should be able to answer both of the questions interviewers love here: "walk me through how the revolver works" and "why is your model circular?"

The debt schedule is a supporting tab, but it is the one that ties the whole model together. It takes cash flow from the rest of the model, decides how much debt gets paid down or drawn, and feeds two numbers back: interest expense to the income statement and debt balances to the balance sheet. Get it right and the model balances every year. Get it wrong and either the balance sheet breaks or the model spins.

Why the debt schedule is the engine room

In a standard three-statement financial model, the debt schedule is what makes the cash actually flow somewhere. Operating cash flow, capex, and working capital produce a cash figure before financing. The debt schedule takes that figure, applies mandatory repayments, runs the cash sweep, and draws on the revolver if there is a shortfall. The ending cash and ending debt balances then flow to the balance sheet, and the interest expense flows to the income statement.

In an LBO, the debt schedule matters even more because the entire investment thesis often rests on debt paydown. A sponsor buys a company with, say, $600 million of debt and $400 million of equity, then uses the target's own cash flow to grind that debt down over five years. Every dollar of debt repaid is a dollar of equity value created at exit, all else equal. If you want the full picture of how that value is generated, our LBO modeling walkthrough shows how the debt schedule connects to returns.

The circular relationship at its core

The reason the debt schedule is harder than any other tab is a genuine circular dependency baked into the finance. Interest expense depends on the average debt balance during the year. The debt balance depends on how much cash you use to pay debt down. The cash available to pay debt down depends on net income, which depends on interest expense. The snake eats its own tail.

You can dodge the loop entirely by calculating interest on the beginning-of-period balance instead of the average, which we cover later. But most polished models use the average balance and manage the circularity deliberately. Either way, you need to understand where the loop comes from before you can control it.

Real capital structures stack several layers of debt, each with its own seniority, pricing, amortization, and prepayment behavior. The debt schedule models each tranche as its own block of rows, and the order matters: cash pays down the most senior, most expensive-to-keep obligations first, then works its way down. Below is the typical waterfall you will see in a leveraged deal.

The revolver

The revolving credit facility, or revolver, is a flexible line of credit the company draws on when it is short of cash and repays when it has a surplus. Think of it as a corporate credit card that sits at the top of the structure. It is rarely fully drawn at close; instead it acts as a liquidity backstop, funding seasonal working capital swings or a bad year without forcing a default. Because it is undrawn most of the time, the lender charges an undrawn commitment fee (often around 0.50%) on the unused portion, plus interest on whatever is drawn.

Revolver (Revolving Credit Facility)

A revolver is a committed line of credit a borrower can draw down, repay, and redraw as needed up to a set limit. In a financial model it functions as the plug that keeps cash from ever falling below a minimum balance: the model draws on it automatically when cash is short and repays it first when cash is available.

Term Loan A and Term Loan B

Term loans are the workhorse tranches. Term Loan A (TLA) is typically held by banks, amortizes heavily (often 5 to 10% of the original balance per year), and is priced tighter. Term Loan B (TLB) is the institutional tranche bought by CLOs and credit funds; it carries only nominal 1% annual amortization (0.25% per quarter) with the rest due as a bullet at maturity, and it prices wider to compensate for the longer duration. In recent markets, broadly syndicated Term Loan B facilities for single-B borrowers have generally priced in the SOFR plus 300s, and new-issue spreads on B-minus rated loans tightened to roughly SOFR plus 366 basis points in late 2025, the lowest since the financial crisis, per PitchBook LCD's leveraged loan market wrap.

The TLB is usually where the cash sweep bites, because its light amortization leaves a large balance outstanding that lenders want repaid faster when the business performs well.

Senior notes and subordinated debt

Below the term loans sit senior notes (high-yield bonds), which are usually unsecured, pay a fixed coupon, and repay as a bullet at maturity with no amortization. Further down still is subordinated or mezzanine debt, the most expensive layer, which absorbs the first losses after equity and often carries a payment-in-kind feature. For a fuller treatment of that layer, see our explainer on mezzanine debt and preferred equity. The lower a tranche sits, the higher its cost and the later it gets repaid, which is exactly why the sweep targets the cheapest-to-retire senior debt first.

Every dollar of debt repayment in your schedule falls into one of two buckets: the company has to make the payment, or it chooses to. Modeling tests almost always want to see both, layered in the right order, because they behave completely differently in a downside case.

Mandatory amortization

Mandatory amortization is the contractual minimum the borrower must repay each period regardless of how the business is doing. For a Term Loan B, that is the 1% per year (0.25% quarterly) of the original principal. It is a fixed dollar amount, calculated off the face value at close, and it does not flex with cash flow. In a model you hardcode the amortization percentage and multiply it by the original balance, then subtract that from the tranche each period until maturity, when the remaining bullet comes due.

Mandatory Amortization

Mandatory amortization is the scheduled principal repayment a borrower is contractually required to make on a term loan each period, typically expressed as a percentage of the original loan amount. Unlike a cash sweep, it is fixed and must be paid whether or not the company generates surplus cash, which is why it sits at the top of the debt schedule waterfall.

Optional prepayment and the cash sweep

Optional prepayment is voluntary repayment above the mandatory minimum, and in leveraged deals it is almost always governed by a cash sweep. The credit agreement forces the borrower to use a defined slice of its surplus cash, called excess cash flow, to prepay debt ahead of schedule. It is technically optional in the sense that it is not a fixed installment, but the covenant makes a portion of it effectively compulsory when cash is available.

Cash Sweep

A cash sweep is a provision in a credit agreement that requires a borrower to use a defined percentage of its excess cash flow to prepay outstanding debt before it is contractually due. It accelerates deleveraging in strong years, protects lenders, and is the mechanism that drives most of the debt paydown in a leveraged buyout model.

The order is what candidates get wrong. Cash flow is applied first to mandatory amortization, then to the revolver, then to the cash sweep on the term loans. Only cash left after the mandatory payments and after restoring the minimum cash balance is available to sweep. Building that order correctly is the single most testable piece of the whole schedule.

Sweep percentages and step-downs

The sweep percentage is rarely a flat number. Credit agreements tie it to a leverage grid so that a healthier, less-levered borrower keeps more of its own cash. The classic broadly syndicated grid starts at 50% of excess cash flow and steps down to 25% and then to zero as net leverage crosses agreed thresholds, though the exact levels vary by deal, and tighter structures, particularly in private credit, can start higher. Law firms that draft these provisions, such as Sidley Austin, note that leverage-based step-downs are now standard in both syndicated and private credit deals.

Because the sweep is a percentage of excess cash flow, you also need to know how excess cash flow is defined in the agreement, since it typically starts from cash flow from operations, subtracts capex, mandatory debt payments, and cash interest, and adjusts for a handful of negotiated items. For interview purposes, the concept matters more than the exact definition: surplus cash after obligations gets shared with lenders on a formula.

The debt schedule is the modeling test question candidates fail most: Work through debt schedules, LBO mechanics, and circularity questions with worked answers on the practice platform, start practicing interview questions for free and find your gaps before an interviewer does.

The revolver is the piece that makes people freeze, because it has to do two opposite jobs in one formula: draw cash when the company is short, and repay when the company has extra. Once you see the logic as a simple comparison against a minimum cash balance, it stops being intimidating.

The minimum cash balance

Every operating model assumes the company needs to keep some cash on hand to run the business: to make payroll, cover timing gaps, and avoid bouncing payments. This is the minimum cash balance, and it is the trigger for the entire revolver mechanic. If projected cash would fall below the minimum, the revolver draws enough to top it back up. If projected cash is above the minimum, the surplus is available to repay the revolver and then feed the sweep.

Cash available for debt paydown

Before the revolver does anything, you calculate how much cash the business has before any revolver activity. Start with beginning cash, add the cash flow the business generated during the period after operating items, capex, and mandatory debt payments, and you get cash available before the revolver. Compare that to the minimum cash balance:

If that figure is positive, the company has surplus cash and the revolver (or the sweep) can absorb it. If it is negative, the company is short and the revolver must draw to cover the gap.

The draw and paydown formula

The revolver logic collapses into two guarded formulas. When cash before the revolver sits below the minimum, you draw the shortfall. When it sits above the minimum, you repay the revolver, but never more than is outstanding and never more surplus than you have. Written out:

The two MAX and MIN functions are what stop the model from doing something absurd, like drawing a negative amount or repaying more revolver than exists. Walk through a concrete example with small numbers so the mechanics are unambiguous.

That single comparison, run every period, is the whole revolver. The elegance is that the same formula handles good years and bad years automatically: it draws when short, repays when flush, and always respects both the minimum cash floor and the outstanding balance.

Some tranches, particularly mezzanine and holdco notes, can pay interest in kind rather than in cash. Instead of writing a check, the borrower rolls the interest into the principal balance, which then compounds. Models handle this with a PIK toggle, a switch that routes interest either to cash (reducing cash available for debt paydown) or to the debt balance (increasing the principal that future interest accrues on).

The reason PIK matters for the debt schedule is that PIK interest does not consume cash, so it never competes with the sweep or the revolver for the same dollars. It does, however, grow the balance, which is why a PIK tranche can end the forecast larger than it began. Our deep dive on payment-in-kind debt covers how PIK interest compounds and why sponsors sometimes prefer it despite the higher effective cost. For a modeling test, you usually just need to build the toggle cleanly and make sure PIK interest hits the balance, not the cash line.

Now the part that causes the actual panic. You finish the debt schedule, link interest expense back to the income statement, and Excel throws a circular reference warning or the whole model collapses to zeros. This is expected, and knowing how to explain and fix it is a genuine differentiator in a modeling test.

Where the circular reference comes from

The loop is precise. Interest expense is calculated on the debt balance. Interest expense reduces net income. Net income feeds cash flow. Cash flow determines how much debt gets swept and how much revolver is drawn. That changes the debt balance, which changes interest expense, which changes net income, and so on around the circle. Excel cannot resolve a formula that depends on its own output unless you tell it to iterate.

Average vs beginning-of-period balances

There is a design choice that determines whether you even have a circularity. If you calculate interest on the beginning-of-period balance, there is no loop: the beginning balance is a fixed number carried from last period, so interest does not depend on this period's paydown.

If instead you calculate interest on the average of the beginning and ending balances, which is more accurate because it reflects paydown happening through the year, you create the circular reference, because the ending balance depends on the paydown that depends on interest.

Neither is wrong. Beginning-balance interest is simpler and safe under time pressure; average-balance interest is more precise and is what many bankers expect on a polished model. Know both and be ready to say which you used and why.

Iterative calculation and the circularity switch

To use average balances without the model erroring out, you enable iterative calculation in Excel (File, Options, Formulas, then check Enable iterative calculation, typically with maximum iterations around 100 and maximum change of 0.001). This tells Excel to loop through the calculation repeatedly until the numbers stop moving, resolving the circular reference to a stable answer.

The switch works by wrapping the interest calculation in a condition: if the switch is on, calculate interest normally; if it is off, return zero. Because interest is the link that closes the loop, zeroing it temporarily severs the circularity and lets the rest of the model recalculate cleanly.

Fixing a model that blows up on a test

When a modeling test model lights up with circular warnings or fills with zeros, work the problem in order rather than randomly clicking cells. First, flip the circularity switch to 0 to break the loop. Second, find and fix the root error, which is usually a #REF from a deleted cell, a #DIV/0 from an empty denominator, or a balance pointed at the wrong period. Third, with iterative calculation confirmed on, flip the switch back to 1 and check that the balance sheet balances.

If you want to see how covenants interact with all of this, since a cash sweep and a leverage-based step-down are covenant mechanics, our guide to maintenance versus incurrence covenants explains the agreements that govern how much a lender can force a borrower to repay.

Interviewers rarely ask you to define a debt schedule in the abstract. They probe whether you actually understand the mechanics by asking you to walk through a specific piece or to diagnose a broken model. Two questions come up again and again.

"Walk me through how the revolver works"

This is the single most common debt schedule question, and the answer they want is the draw-and-repay logic in plain English. Say that the revolver is a line of credit that keeps the company from ever running below its minimum cash balance: if projected cash before the revolver falls below the minimum, the revolver draws the shortfall; if projected cash is above the minimum, the surplus repays the revolver first, capped at the outstanding balance, and any remaining cash flows to the sweep on the term loans. Mention that it charges a commitment fee on the undrawn portion and interest on the drawn portion. A crisp thirty-second version of that mechanic signals you have built one, not just read about it.

"Why is your model circular?"

When an interviewer asks this, they are testing whether you understand the interest-to-cash loop, not whether you made a mistake. The right answer names the loop: interest expense depends on the debt balance, the debt balance depends on how much cash sweeps or draws, and the cash depends on net income, which depends on interest, so the calculation feeds itself. Then explain your fix: either calculate interest on the beginning balance to avoid the loop entirely, or use the average balance with iterative calculation turned on and a circularity switch to break the loop when it errors out. Candidates who can also explain the tradeoff between the two approaches stand out.

Get the complete technical toolkit: Download our comprehensive 160-page PDF, access the IB Interview Guide covering debt schedules, LBO mechanics, and every technical framework interviewers test.

For deeper practice on what evaluators actually score during a modeling exercise, our breakdown of what interviewers look for in Excel modeling tests covers the habits, from clean formatting to error-checking, that separate a pass from a fail.

The debt schedule earns its reputation as the hardest tab in the model, but the difficulty is mechanical, not conceptual. It rewards candidates who build it in the right order and who understand that the circularity is a feature of the finance, not a flaw in their work. If you can lay out the tranche waterfall, apply mandatory amortization before the sweep, restore the minimum cash balance before repaying the revolver, and explain calmly why interest expense makes the model circular, you will handle the debt schedule better than most people sitting for the same test.

Practice the actual build, not just the reading. Open a blank model, hardcode a small capital structure with a revolver and a Term Loan B, and force yourself through a good year and a bad year until the draw, the paydown, and the sweep behave without you thinking about the formulas. When an interviewer says "walk me through how the revolver works" or "why is your model circular?", the answer should come as easily as describing something you have done a dozen times, because you will have. Pair that fluency with a clear grasp of debt capacity, and you will be ready for the technical questions that trip up nearly everyone else.