Subordinated Debt vs Mezzanine Financing: How Junior Capital Works

Most operating businesses meet the capital stack from the bottom up. A bank, a factor, or an asset-based lender provides the senior facility, the owners hold the equity, and at some point the business needs more capital than the senior lender will advance. That middle ground is junior capital, and its two most-used terms, subordinated debt and mezzanine financing, overlap without being identical. The differences show up exactly when they matter most: in what gets paid first when cash is tight, what security the junior lender holds, and whether part of the price is a slice of your company.

What is the difference between junior debt and senior debt?

Senior debt is the debt that ranks first in the capital stack: it is repaid ahead of every junior layer and, when secured, holds the first claim on collateral. Everything that ranks below senior debt and above common equity is junior capital.

Junior debt is the broad market term for any capital that ranks behind senior debt, whether by lien (second lien) or by right of payment (subordinated or mezzanine debt). Proskauer describes junior capital as the products that sit “between senior debt and common equity” (Proskauer, The Secured Lender, 2008).

In everyday usage the labels blur (the Corporate Finance Institute opens its definition with “Junior debt, also referred to as subordinated debt”), but loan documents treat lien priority and payment priority as different things, and our guide to the capital stack maps every layer from senior debt to common equity.

What is subordinated debt?

Subordinated debt is debt whose holder has contractually agreed not to be paid until senior debt is paid in full. The agreement is the point: subordination is a promise the junior lender makes to the senior lender, usually written into a subordination or intercreditor agreement.

Under payment subordination, “the borrower is prohibited from making payments on the junior debt until the senior creditor’s debt is satisfied,” as Mayer Brown puts it (Mayer Brown, June 2026). A&O Shearman notes that payment subordination “renders the junior debt subordinated in its right to recovery from all sources” (A&O Shearman via Mondaq, 2019), not just from one pool of collateral. That reach, across every source of repayment, is what separates true subordinated debt from a second lien.

Contractual vs structural subordination

Subordination can be built two ways. Contractual subordination is priority set by agreement between lenders to the same borrower. Structural subordination is priority set by corporate structure: the junior lender lends to a holding company while the senior lender lends to the operating company that holds the assets. A structurally subordinated lender sits behind the operating company’s unsecured creditors, as Bass, Berry & Sims explains.

The terms of either kind live in the agreement between the lenders. Our explainer on what an intercreditor agreement is covers how those documents allocate payments, remedies, and consent rights.

What is mezzanine financing?

Mezzanine financing is capital that sits between senior debt and equity, usually unsecured and subordinated to the senior lender in right of payment, often combining cash interest with PIK interest and sometimes accompanied by warrants. The name describes the position, a level between the senior debt and the owners’ equity, which is how EdgePoint Capital Advisors frames the product.

Proskauer’s description is direct: “A mezzanine loan is unsecured and subordinated to the senior lender’s loan with respect to the right to receive payments” (Proskauer). Bass, Berry & Sims adds that mezzanine obligations “are unsecured or are secured solely by a pledge of the equity interests in the borrower and/or by a second lien” (Bass, Berry & Sims). The ABA’s model intercreditor task force observed that payment subordination is “typically found in unsecured mezzanine financing” (ABA Business Law Section, 2010).

How do mezzanine lenders get paid?

Mezzanine pricing usually has more than one component. Part is cash interest, and part is often payment-in-kind interest. Payment-in-kind (PIK) interest is interest paid by issuing additional notes instead of cash, so it accrues to principal and is paid at a later time. Proskauer describes interest “paid-in-kind (PIK) by the issuance of additional notes” (Proskauer), and EdgePoint notes that it “accrues to principal and is paid at a later time.”

A mezzanine loan is also “sometimes accompanied by warrants,” per Proskauer, and these are often “penny warrants” (EdgePoint): rights to buy equity at a nominal price, which give the lender a share of the company’s upside.

How is second lien debt different from subordinated debt?

Second lien debt is subordinated only with respect to collateral, while subordinated debt is subordinated with respect to payment. That one distinction drives very different outcomes when a business is under stress. Second lien debt is debt secured by a junior lien on the same collateral that secures the first lien debt.

Lien subordination ranks only the claim on shared collateral. Without payment subordination, a second lien lender can still be paid from sources other than that collateral, as Mayer Brown explains. A&O Shearman describes second lien debt as “pari passu with the first lien debt for non-collateral based recoveries” (A&O Shearman via Mondaq), and Proskauer states plainly that “there is no payment subordination in a second lien intercreditor” (Proskauer).

In practical terms: if the collateral falls short, a second lien lender shares in recoveries from other sources alongside the first lien lender rather than behind it. A subordinated lender, by contract, waits until the senior lender is paid in full from all sources.

Is mezzanine financing the same as subordinated debt?

Not exactly. Mezzanine financing is generally a form of subordinated debt, but not all subordinated debt is mezzanine. Subordinated debt describes a ranking; mezzanine describes a product built on that ranking, usually with PIK interest, sometimes warrants, and a sponsor, acquisition, or growth use case.

The table below sets senior debt, second lien debt, subordinated debt, and mezzanine financing side by side. Terms in any real deal are negotiated, so read it as the typical shape of each instrument, not a rule.

Compare the four structures. Scroll horizontally on smaller screens.

Table sources: Proskauer (2008), Bass, Berry & Sims (2019), A&O Shearman (2019), Mayer Brown (2026), EdgePoint (2019), SPP Capital Partners (September 2026). Typical features only; actual terms are negotiated deal by deal.

What are the disadvantages of subordinated debt?

The disadvantages of subordinated debt are cost, compounding, possible dilution, and loss of control over timing. Because the junior lender takes more risk than the senior lender, it charges more, and the intercreditor terms that protect the senior lender constrain both the junior lender and the borrower.

Beyond the rate, the structure carries costs of its own:

• PIK compounding. PIK interest accrues to principal, so the balance grows whenever interest is not paid in cash (EdgePoint; Proskauer). It defers the cash cost; it does not remove it.
• Dilution. Warrants, often penny warrants, give the lender a slice of the equity (EdgePoint). Owners give up some of the upside the debt was meant to protect.
• Payment blockage. Under typical subordination terms, a senior payment default “will always trigger a permanent payment blockage” on the junior debt, and other senior defaults block junior payments for a period, usually 90 to 180 days, per Bass, Berry & Sims.
• Standstill on remedies. A subordinated lender typically agrees to a standstill period before it can enforce remedies after a default (Bass, Berry & Sims; Proskauer).
• Harder renegotiation. Intercreditor agreements commonly require the senior lender’s consent to amend the junior debt, which can make a restructuring harder to negotiate (Proskauer; Bass, Berry & Sims).

When does subordinated debt, mezzanine, or equity make sense?

Junior debt tends to make sense when senior debt is capped and new equity would be expensive or dilutive. It fills the space between what the senior lender will advance and what the business needs, with less dilution than an equity raise would typically require.

The trade-off starts with the basic debt-versus-equity comparison. Mayer Brown’s Fundamentals of Capital Structures lists debt’s advantages as “Tax deductibility of interest expense,” a “Cheaper source of capital than equity,” and “No dilution of ownership,” and describes equity as a “More expensive source of capital than debt” that “Creates dilution” (Mayer Brown). Debt brings a cash flow commitment that equity does not carry. Mezzanine sits deliberately between the two: more expensive than senior debt, generally cheaper than equity, and sometimes partly dilutive through warrants. Our breakdown of debt, equity, and hybrid capital structures goes deeper on those trade-offs.

Senior capacity is the constraint to watch. Among lower middle market issuers (under $5MM EBITDA), SPP reports that “leverage capacity is contracting and lender scrutiny is intensifying,” and it put total debt to EBITDA at 2.50x to 3.25x for issuers under $10MM EBITDA as of September 2026 (SPP Capital Partners).

A practical way to sequence the decision:

• Start with senior capacity. It is usually the lowest-cost layer, so size it first.
• Consider subordinated debt when the senior lender caps out below the need and the business can carry another repayment commitment.
• Consider mezzanine when a sponsor, acquisition, or growth plan needs a larger junior layer and the owners accept PIK interest or warrants as part of the price.
• Consider equity when the business cannot carry a further cash flow commitment and dilution is the better trade.

Where does Stretch Financing fit?

Stretch Financing is Capital Source’s junior capital program for growing businesses that need more than their senior facility can provide. It typically sits in a subordinate position behind a factor’s or asset-based lender’s senior facility, is typically repaid on a revenue-based or performance-based model, and is typically structured as non-dilutive.

That makes it one form of junior capital, built for a different situation than sponsor-style mezzanine. This guide’s discussion of mezzanine, warrants, and sponsor-backed debt is educational; Stretch Financing is a different structure. The common trigger is the gap above the borrowing base: the business is growing, the senior facility advances against eligible receivables or inventory, and the capital the business needs runs ahead of what that formula allows. Our article on the gap above the borrowing base walks through how that gap forms.

Learn more about Stretch Financing. Capital Source’s financing is offered through our affiliate, Stretch Finance, LLC. Availability, amount, and terms are subject to underwriting.

Key takeaways

• Junior debt is the umbrella. Second lien, subordinated, and mezzanine debt all rank behind senior debt, in different ways.
• Lien priority is not payment priority. Second lien debt ranks behind only on shared collateral; subordinated debt waits on payment from all sources.
• Subordinated is a ranking; mezzanine is a product. Mezzanine usually adds PIK interest, sometimes warrants, and a sponsor, acquisition, or growth use case.
• The cost is more than the rate. PIK compounding, possible dilution, payment blockage, standstills, and consent rights all shape what junior debt really costs.
• Stretch Financing is one form of junior capital. It typically sits behind a factor’s or asset-based lender’s senior facility, is typically repaid on a revenue-based or performance-based model, and is typically structured as non-dilutive.

Frequently asked questions

Sources

• Mayer Brown, Lien vs. Payment Subordination in Fund Finance, June 23, 2026.
• A&O Shearman (via Mondaq), Delaware Bankruptcy Court Intercreditor Decision Raises Claim Subordination Issues, March 1, 2019.
• Bass, Berry & Sims, Stuck in the Middle of the Cap Stack, June 2019.
• Proskauer (Ellis and Boyko), The Ever-Changing Layer Cake of Junior Capital Financing and Intercreditor Agreements, The Secured Lender, May/June 2008.
• ABA Business Law Section, Report of the Model First Lien/Second Lien Intercreditor Agreement Task Force, May 6, 2010.
• Mayer Brown, Fundamentals of Capital Structures (PLI Pocket MBA), November 2019.
• SPP Capital Partners, Market At A Glance, September 2026.
• EdgePoint Capital Advisors, Subordinated Debt/Mezzanine Capital, January 2019.
• Corporate Finance Institute, Junior Debt, December 13, 2020.

This article is for informational and educational purposes only and does not constitute financial, investment, accounting, tax, or legal advice. The concepts discussed are general in nature and should be reviewed with qualified professionals based on your specific circumstances. Capital Source provides access to commercial financing solutions through its affiliates, syndicates, network of banks, lending partners, and private credit funds/groups. Availability, approval, funding amount, structure, and terms are subject to business review, underwriting, and lender approval.