LBO Debt Structures: Senior, Subordinated, and Mezzanine

Introduction

The debt structure is the architectural core of every leveraged buyout. How the debt is layered, what it costs, and how it amortizes determine the company's interest burden, free cash flow available for debt repayment, and ultimately the sponsor's equity returns. Designing the optimal debt structure requires balancing two competing objectives: maximize leverage (to minimize the equity check and amplify returns) while maintaining adequate debt service capacity (to avoid financial distress during the holding period).

This article walks through the standard layers of the LBO capital stack, from the most senior (lowest cost, highest priority) to the most junior (highest cost, lowest priority).

Senior Secured Debt

Senior secured debt sits at the top of the capital stack: it is repaid first in any bankruptcy or liquidation, and it is secured by the company's assets (typically a first-lien on all assets). Because of this priority and security, senior debt carries the lowest interest rate of any debt layer.

Revolving credit facility (revolver): A flexible borrowing facility that the company can draw on and repay as needed, similar to a corporate credit card. The revolver is sized based on the company's working capital needs and is typically undrawn at closing (reserved for future liquidity needs). Interest is paid only on amounts drawn, plus a small commitment fee on the undrawn portion.

Term Loan A (TLA): An amortizing term loan with a scheduled principal repayment over its life (typically 5-7 years). TLA is provided by the same bank syndicate that provides the revolver and has the same interest rate (SOFR + 200-300 bps typically).

Term Loan B (TLB): The workhorse of LBO financing. TLB has minimal amortization (typically 1% per year, with the balance due at maturity in 6-7 years). It is syndicated to institutional investors (CLOs, loan funds, hedge funds) rather than held by banks. TLB carries a higher spread than TLA, though 2025 saw record spread compression: the average institutional loan margin fell to 3.13% (SOFR + ~313 bps) in Q3 2025, the lowest quarterly average on record, driven by intense competition among lenders to deploy capital. This compression has meaningful implications for LBO economics, as lower borrowing costs directly increase free cash flow for debt repayment and boost sponsor returns.

Term Loan B (TLB)

An institutional term loan that is the primary debt instrument in most leveraged buyouts. TLB has minimal scheduled amortization (typically 1% annual principal repayment), a bullet maturity of 6-7 years, and is syndicated to institutional investors rather than held by banks. The low mandatory amortization maximizes the cash flow available to the company during the holding period, which is attractive to sponsors because more cash can be directed toward operations and voluntary prepayments. TLB pricing is typically SOFR + 300-500 basis points, depending on the borrower's credit profile and market conditions.

Senior Unsecured Debt (High-Yield Bonds)

High-yield bonds sit below senior secured debt in the capital stack. They are unsecured (no collateral) and have a lower claim on assets in bankruptcy. The tradeoff for lenders is a higher interest rate (typically 6-10% in the current environment) and longer maturity (7-10 years).

High-yield bonds have no scheduled amortization: the entire principal is due at maturity (bullet payment). This is advantageous for the sponsor because it preserves cash flow during the holding period. However, the higher interest rate increases the annual interest expense.

High-yield bonds also have different covenant structures than bank debt. They typically feature incurrence covenants (tested only when the company takes specific actions, like issuing more debt or making a distribution) rather than maintenance covenants (tested quarterly regardless of actions). This difference gives the company more operational flexibility.

Subordinated Debt

Subordinated debt ranks below senior debt in the priority waterfall. In a bankruptcy, subordinated lenders are repaid only after senior secured and senior unsecured claims are fully satisfied. The higher risk is compensated with a higher interest rate (typically 8-12%).

Subordinated debt may be structured as subordinated notes (with cash-pay interest) or as PIK (payment-in-kind) instruments where interest accrues and is paid at maturity rather than in cash. PIK structures preserve cash flow during the holding period but increase the total debt burden over time.

Mezzanine Financing

Mezzanine debt is the most junior form of debt in the capital stack, sitting just above equity. It carries the highest interest rate (12-18%) and often includes equity warrants or conversion features that give the mezzanine lender upside participation if the deal performs well.

Mezzanine financing is used to fill the gap between senior debt capacity and the equity check. If the total purchase price is $1 billion, senior debt capacity is $500 million, and the sponsor wants to limit its equity check to $350 million, the $150 million gap is filled by mezzanine financing.

The blended cost of debt (the weighted average across all tranches) flows into the WACC calculation if the analyst is building a DCF alongside the LBO model.

Most LBO targets receive credit ratings from Moody's and S&P immediately after the transaction closes. The ratings assess the company's ability to service its debt obligations and directly affect the pricing, structure, and market appetite for the debt.

LBO targets typically receive sub-investment-grade ratings (below BBB-/Baa3) because the high leverage inherent in the buyout structure increases default risk. The most common rating range for LBO credits is B+ to B- (S&P) or B1 to B3 (Moody's), though higher-quality credits with strong cash flows can achieve BB ratings, and highly leveraged or riskier deals may receive CCC ratings.

The rating determines which investors can purchase the debt. Investment-grade investors (insurance companies, pension funds, and many mutual funds) are restricted from holding sub-investment-grade paper. LBO debt is instead purchased by CLOs (collateralized loan obligations), high-yield mutual funds, hedge funds, and direct lending firms. This investor base is more yield-oriented and more tolerant of leverage, but it also demands higher spreads than the investment-grade market.

Importantly, the rating agencies evaluate the entire capital structure, not just individual tranches. A company with 6x total leverage will receive a lower corporate rating (and pay higher spreads on all debt tranches) than the same company with 4x leverage, even if the senior secured debt is identical in both structures. This interaction between total leverage and individual tranche pricing is one reason the capital structure decision is so consequential: adding an incremental turn of leverage may not only increase the interest cost on the new debt but can also widen the spread on existing debt through a rating downgrade.

To ground these concepts in a real transaction, consider the Electronic Arts $55 billion take-private in September 2025, the largest LBO in history. The consortium (Saudi Arabia's Public Investment Fund, Silver Lake, and Affinity Partners) financed the deal with approximately $36 billion in equity and $20 billion in debt, a roughly one-third debt, two-thirds equity split that was notably conservative for an LBO of this scale. JPMorgan provided the $20 billion debt commitment, structured across senior secured term loans, a revolving credit facility, and high-yield bonds. This deal illustrates that even the largest LBOs can be structured conservatively when sponsors have access to substantial equity capital and prioritize financial flexibility over leverage-driven returns.

In the middle market, capital structures are simpler. A $500 million LBO might use only a revolver and a single TLB (or a unitranche), with the sponsor writing the equity check for the remainder. The multi-tranche structures described above become necessary as deal size increases and the debt need exceeds what any single lender or market can provide.

One of the most significant shifts in LBO financing over the past decade is the rise of direct lending (also called private credit). Private credit funds now finance approximately 86% of LBOs (by count) as of mid-2025, fundamentally reshaping the market. Instead of banks syndicating loans to institutional investors, private credit firms provide the full debt commitment directly.

Direct lending offers sponsors speed (no syndication process), certainty (committed financing without market risk), and flexibility (more accommodating covenant packages). The tradeoff is cost: direct lending spreads are typically 100-200 basis points wider than broadly syndicated loans, reflecting the premium for certainty and customization. However, the competitive pressure from the flood of private credit capital has compressed even direct lending spreads, with over 81% of direct-lending LBOs in 2025 priced below SOFR + 550 bps.

This evolution matters for valuation because the availability and cost of financing directly affects the LBO floor. When private credit is abundant and competitively priced, sponsors can pay higher entry multiples (because the debt is cheaper) and the LBO floor rises closer to strategic buyer pricing.

The debt structure established at closing is not static. Sponsors actively manage and optimize the capital structure throughout the holding period through refinancing, which involves replacing existing debt with new debt on more favorable terms.

Common refinancing objectives include:

Reducing the interest rate. If market spreads have tightened since the original financing or if the company's credit profile has improved (higher EBITDA, lower leverage), the sponsor can refinance existing debt at a lower rate, increasing free cash flow and boosting equity returns. A $500 million TLB repriced from SOFR+400 to SOFR+300 saves approximately $5 million annually in interest expense.

Extending maturities. If a significant debt tranche is approaching maturity in 2-3 years, the sponsor refinances early to push the maturity out, removing near-term repayment pressure and giving more runway for the exit. Lenders call this "amend and extend."

Adding leverage for dividend recaps. As discussed above, refinancing can increase total leverage to fund a dividend to the sponsor, returning capital without requiring an exit event.

Switching from bank debt to bonds. If the bond market offers more favorable terms or more covenant flexibility than the existing bank facility, the sponsor may refinance the bank debt with a high-yield bond issuance.

Refinancing activity is highly cyclical, peaking when credit markets are loose and spreads are tight. In 2024-2025, refinancing and repricing volume surged as sponsors took advantage of compressed spreads to reduce borrowing costs across their portfolios. According to Leveraged Commentary & Data (LCD), approximately $1.3 trillion in leveraged loans were repriced or refinanced in 2024, a record reflecting the favorable market conditions.

Maintenance Covenants

Tested quarterly regardless of the company's actions. If the company breaches a maintenance covenant (e.g., total leverage exceeds 6.0x or interest coverage falls below 2.0x), the lenders can accelerate repayment or force a restructuring. Maintenance covenants are standard in revolvers and Term Loan A facilities.

Incurrence Covenants

Tested only when the company takes a specific action (issuing new debt, making a restricted payment, executing a dividend recapitalization). If the company cannot pass the incurrence test, it cannot take the action. High-yield bonds typically use incurrence covenants, giving the company more day-to-day operational flexibility.

A dividend recapitalization (dividend recap) occurs when the portfolio company borrows additional debt and uses the proceeds to pay a special dividend to the sponsor. This allows the PE firm to return capital to its limited partners without selling the company, effectively de-risking the investment while retaining ownership.

Dividend Recapitalization

A transaction in which an LBO portfolio company issues new debt and uses the proceeds to pay a cash dividend to its private equity sponsor. The recap increases the company's leverage but returns cash to the sponsor, reducing (or sometimes fully recovering) the original equity investment. A sponsor that invested $400 million in equity and subsequently executes a $200 million dividend recap has effectively reduced its at-risk capital to $200 million while still owning 100% of the company. If the company is later sold or goes public, the entire exit proceeds accrue to the sponsor's remaining equity position, dramatically amplifying the return on the residual invested capital.

Dividend recaps are controversial because they increase the company's debt burden without adding any operational value. The additional leverage reduces the company's financial flexibility and increases the risk of covenant breach or distress. Critics argue that sponsors use recaps to inflate IRRs by returning capital early (since IRR is time-weighted, receiving cash sooner boosts the return metric even if the total proceeds are unchanged). Proponents argue that recaps are a rational capital allocation decision: if the company can support additional debt, returning excess capital to investors is more efficient than leaving it idle on the balance sheet.

The ability to execute a dividend recap depends on the covenant structure. Incurrence covenants in high-yield bonds and covenant-lite term loans often permit restricted payments (including dividends) up to a specified "builder basket" amount, which grows as the company generates retained earnings. Tight maintenance covenants in traditional bank debt may restrict dividend payments, which is one reason sponsors prefer covenant-lite structures.

In the current market, dividend recaps have surged. Sponsors who acquired companies in 2019-2021 and have been unable to exit at attractive valuations have used recaps to generate distributions for LPs (limited partners), partially addressing the liquidity crunch created by slow exit activity. By Q3 2025, recap loan volume approached the record levels seen in 2021, reflecting both the demand for LP distributions and the willingness of private credit lenders to support these transactions.

One of the most significant structural shifts in leveraged finance over the past 15 years is the migration from maintenance covenants (standard in traditional bank-led LBOs) to covenant-lite structures (standard in today's institutional market).

In a traditional leveraged loan, the company must meet quarterly financial tests (total leverage below a specified ratio, interest coverage above a specified ratio). If the company misses these tests, the lenders have the right to accelerate repayment, effectively giving them veto power over the company's operations.

In a covenant-lite loan, these quarterly tests are eliminated. The company must comply with incurrence covenants (tested only when it takes specific actions like issuing additional debt or paying dividends), but it is free from ongoing financial testing. This means a company can experience a significant EBITDA decline without triggering a technical default, as long as it continues to make its interest payments.

The shift to covenant-lite has been dramatic. In 2007, covenant-lite loans represented approximately 25% of the institutional leveraged loan market. By 2025, they represent over 90%. This evolution benefits sponsors (more operational flexibility, less lender interference) but concerns credit analysts and rating agencies (weaker protections mean lenders have less ability to intervene before a company's financial position deteriorates beyond recovery).