LBO Model Explained: How to Build One Step by Step

An LBO model is a spreadsheet that projects how a private equity firm buys a company mostly with debt, pays that debt down with the company's own cash flow over several years, and sells the company to calculate a return. It is built in the order the deal actually happens: purchase price and sources and uses first, then an operating forecast, then a debt schedule that includes a cash sweep, then the exit and returns calculation. Wall Street Prep frames the build around five stages: purchase assumptions, sources and uses, the operating forecast, the debt schedule, and exit returns. This guide walks through each stage, what goes into it, and how the pieces feed each other, so you understand the mechanics behind the interview one-liner.

What is an LBO model?

An LBO model is the spreadsheet version of a leveraged buyout: it forecasts the target's financial performance, tracks how debt gets repaid, and computes the sponsor's IRR and MOIC at a chosen exit year. Unlike the interview answer to "walk me through an LBO," which is a 90-second verbal framework (see walk me through an LBO), the model is the actual working file: dozens of linked tabs covering assumptions, the operating build, the debt schedule, and returns. A "paper LBO," the pen-and-paper interview exercise covered in how to solve a paper LBO, compresses this same structure into rounded mental math with no spreadsheet at all.

What are the 5 stages of building an LBO model?

The 5 stages, in build order, are purchase price assumptions, the sources and uses table, the operating forecast, the debt schedule with a cash sweep, and the exit returns calculation. Each stage depends on the one before it, which is why the order matters as much as the content.

How do you set the purchase price assumptions?

The purchase price assumptions stage sets entry enterprise value as the entry multiple times the target's EBITDA, which becomes the "uses" side of the deal. A typical assumption block includes the entry EV/EBITDA multiple, the target's trailing or forward EBITDA, and any assumed transaction fees (advisory fees run roughly 2 percent of enterprise value, per Wall Street Prep). This single number, entry enterprise value, is the anchor the rest of the model builds from: everything on the sources side has to sum to it, plus fees and any refinanced debt.

How does the sources and uses table work?

The sources and uses table lists exactly where the deal's financing comes from against exactly what it pays for, and the two columns must sum to the same total. The uses side is purchase price, refinanced existing debt, and transaction and financing fees. The sources side is the debt tranches (senior debt, subordinated or mezzanine debt), any management rollover equity, and the sponsor's cash equity, which is sized as the plug: total uses minus every other source. This table is built once, near the top of the model, and every debt tranche's starting balance flows straight into the debt schedule. Full line-item detail and a worked example are in sources and uses of funds explained.

How is the operating forecast built?

The operating forecast projects revenue, EBITDA, and unlevered free cash flow over the hold period, typically five years, using assumptions for growth, margins, capex, and working capital. It is built the same way any three-statement forecast is built, revenue down to EBITDA, then EBITDA down to free cash flow before financing items. What makes it LBO-specific is that free cash flow here is the input to the debt schedule, not just a valuation output: every dollar of free cash flow either services interest, covers mandatory amortization, or gets swept to pay down principal early. A cyclical or capital-intensive forecast, where free cash flow swings unpredictably, breaks the whole model downstream because the debt schedule cannot rely on it.

How does the debt schedule work?

The debt schedule tracks each debt tranche's balance year by year: beginning balance, interest expense, mandatory amortization, optional prepayment (the cash sweep), and ending balance, which rolls into the next year. Wall Street Prep models tranches separately, senior secured debt (often a revolver plus Term Loan A or B), then subordinated or mezzanine debt below it, because each has its own interest rate and repayment priority. Interest expense is typically calculated off the average of the beginning and ending balance for the year, which means the schedule has a circular reference: interest depends on the ending balance, and the ending balance depends on cash flow after interest. Models resolve this with an iterative calculation setting or a circularity switch. See LBO capital structure for how the tranches differ in cost and priority.

What is the cash sweep and how is it modeled?

The cash sweep is the line in the debt schedule that takes free cash flow left over after mandatory items and applies it to prepay the most senior outstanding debt first. It's the optional prepayment of debt using excess free cash flow ahead of the scheduled repayment date, and most credit agreements pair it with a mandatory excess cash flow sweep that requires a set percentage, commonly 50 to 75 percent, of remaining cash to go to debt paydown. Modeling it requires a minimum cash balance the company must retain, a repayment waterfall (revolver, then Term Loan A, then Term Loan B, then subordinated debt), and a cap so the sweep never pushes any tranche's balance below zero. The full mechanics, including the waterfall order and formula, are in cash sweep in an LBO.

How is the exit value and return calculated?

The exit stage applies an exit multiple to the final projection year's EBITDA to get exit enterprise value, subtracts whatever debt remains on the schedule to get exit equity value, then divides exit equity by the sponsor's entry equity for MOIC and annualizes that for IRR. A conservative model sets the exit multiple equal to, or below, the entry multiple, so the return has to come from EBITDA growth and debt paydown rather than the market being kinder at exit than at entry. In the standard worked example, $100 million of EBITDA at a 10x entry with 60 percent debt produces a $400 million equity check; five years later, $150 million of EBITDA at a 9x exit and $250 million of debt repaid produces $1,000 million of exit equity, a 2.5x MOIC and roughly 20 percent IRR.

Exit Equity = (Exit Multiple × Exit EBITDA) − Remaining Debt, and MOIC = Exit Equity / Entry Equity

What is a returns attribution or bridge?

A returns attribution bridge, sometimes called a value creation bridge, breaks the total dollar gain in equity value into the three drivers: debt paydown, EBITDA growth, and multiple expansion (or contraction), so the sponsor can see which lever actually did the work. It is typically the last tab built, since it just decomposes the entry-to-exit equity change that the rest of the model already produced. Sponsors and interviewers both use this bridge to sanity-check a deal: a return driven mostly by multiple expansion is viewed as weaker and riskier than one driven by deleveraging and operating growth, because multiple expansion is outside anyone's control.

What's the difference between a full LBO model and a paper LBO?

A full LBO model is a linked spreadsheet with a real debt schedule, three-statement projections, and an exact IRR calculated year by year; a paper LBO is the same structure compressed into rounded mental math done by hand in 5 to 10 minutes with no spreadsheet. The paper version tests whether you understand the framework before anyone hands you a keyboard. See how to solve a paper LBO for the mental-math shortcuts, and LBO interview questions for the full set of concept questions interviewers ask around the model.

Sources

• Wall Street Prep, "LBO Model": https://www.wallstreetprep.com/knowledge/lbo-model/ (checked July 2026)
• Corporate Finance Institute, "Leveraged Buyout (LBO)": https://corporatefinanceinstitute.com/resources/valuation/leveraged-buyout-lbo/ (checked July 2026)
• Breaking Into Wall Street, "LBO Model Interview Questions": https://breakingintowallstreet.com/kb/leveraged-buyouts-and-lbo-models/lbo-interview-questions/ (checked July 2026)