Tranche

A tranche is a ranked slice of a securitized bond deal, each carrying its own credit rating, yield, and position in the payment waterfall. In commercial real estate, tranches divide a CMBS pool into layers from AAA senior bonds to unrated subordinate pieces, so senior investors are paid first and absorb losses last.

How Does a Tranche Work?

A tranche works by defining where a slice of bonds sits in the payment and loss waterfall of a securitized pool. Senior tranches receive principal and interest first and absorb losses last, so they earn the highest rating and lowest yield. Junior tranches are paid last and absorb the first losses, so they carry lower ratings and higher yields.

Each tranche is bounded by an attachment point and a detachment point, expressed as percentages of the pool. The attachment point is the loss level at which the tranche starts taking losses, and the detachment point is where it is wiped out. Per FRM structured-credit materials, a tranche with a 7% attachment point loses nothing until cumulative pool losses exceed 7%.

Per KBRA and NRSRO data, CMBS bonds in 2024 carried roughly 30% subordination beneath the AAA tranche, meaning 30% of the pool must be lost before the senior bonds take a dollar of loss.

Why Tranches Matter

Tranches matter because they let a single loan pool serve investors with opposite risk appetites, which is what makes securitization function. A pension fund can buy AAA senior tranches for safety, while a specialist B-piece buyer takes the first-loss subordinate tranche for high yield and control rights. Without tranching, one pool could not price to both.

The structure also concentrates risk in a way that must be understood. Junior tranches can be entirely wiped out while senior tranches stay untouched, so two investors in the same deal can see completely different outcomes. Per FasterCapital, senior tranches are the first to be repaid on default and the last to absorb loss, which is the entire point of the ranking.

The quotable point: a tranche is not a share of the deal, it is a position in line, and the position, not the pool, determines whether an investor is paid in full or wiped out.

Example

A $500,000,000 CMBS pool is divided into three tranches. The pool then suffers $40,000,000 in cumulative losses. The table walks through how the loss is absorbed from the bottom up, using each tranche's attachment and detachment points.

The $40,000,000 loss first wipes out the entire $35,000,000 subordinate tranche, which spans 0% to 7% of the pool ($35,000,000 divided by $500,000,000 equals 7%). The remaining $5,000,000 of loss then reaches the mezzanine tranche, which starts absorbing at the 7% attachment point. The senior AAA tranche, attaching at 25% ($125,000,000 of losses), stays untouched.

Variations and Edge Cases

Tranches take different forms depending on how the deal allocates principal, interest, and time, not just credit rank. Sequential-pay, pro-rata, interest-only, and principal-only structures each change when and how a tranche is repaid, altering its risk even at the same rating. The table covers the distinctions an investor should confirm before pricing a bond.

An edge case worth flagging: the most subordinate tranche, the B-piece, usually carries control rights. Per the CRE Finance Council, the controlling-class holder can typically replace the special servicer, so the first-loss tranche buyer effectively steers workouts across the entire pool.

Tranche vs Bond

A tranche is often confused with a bond, and every tranche is issued as bonds, but the terms are not interchangeable. A tranche is one ranked layer within a securitized deal, defined by its place in the loss waterfall. A bond is a single debt security; a plain corporate bond has no waterfall of senior and junior slices behind it.

The practical difference is structure and correlation. Two tranches from the same deal share one collateral pool but can pay or default independently based on rank. Two unrelated bonds share no collateral and no waterfall, so their outcomes are linked only by the market, not by a common structure.

Frequently Asked Questions

What is a tranche?A tranche is a ranked slice of a securitized bond deal, each with its own credit rating, yield, and position in the payment waterfall. In CMBS, tranches range from AAA senior bonds paid first to unrated subordinate pieces that absorb the first losses.

What is the difference between a senior and a subordinate tranche?A senior tranche is paid principal and interest first and absorbs losses last, earning the highest rating and lowest yield. A subordinate tranche is paid last and absorbs the first losses, so it carries a low or no rating and the highest yield.

How do tranches absorb losses?Tranches absorb losses from the bottom up, defined by attachment and detachment points. The first-loss tranche takes losses until it is wiped out, then the next tranche up begins absorbing, and so on, so senior tranches are hit only after all junior tranches are exhausted.

Related Terms

• CMBS Loan

• Capital Stack

• Mezzanine Debt

• Senior Debt

• Debt Service Coverage Ratio