Collateralised Loan Obligations (CLOs)

How the structure works

A collateralised loan obligation begins with a special-purpose issuer buying a portfolio of typically one to three hundred broadly syndicated leveraged loans: senior secured, floating-rate debt issued by companies rated below investment grade. That purchase is funded not with equity capital in the ordinary sense but by issuing a stack of securities against the pool — AAA notes at the top, then AA, A, BBB and BB notes, and finally an unrated equity or residual tranche at the bottom.

Cash generated by the loans runs down a waterfall. Fees to the trustee and manager come off the top, then interest is paid to each note tranche in strict order of seniority, and only what remains flows to equity. Losses run the opposite direction: the equity tranche absorbs the first defaults in the portfolio, and a senior tranche is touched only after every tranche below it has been wiped out.

A collateral manager actively trades the loan portfolio during a reinvestment period lasting several years, replacing repaid or sold loans with new ones. After that period ends, loan repayments stop being reinvested and instead pay down the notes starting from the top of the stack.

Overcollateralisation and interest-coverage tests function as the structure's circuit breaker. When the portfolio's credit quality or coverage ratios fall past a defined threshold, cash that would otherwise flow to junior tranches is diverted to pay down senior notes instead, protecting the top of the stack at the direct expense of the bottom.

What each tranche pays

Both the underlying loans and the notes issued against them are floating rate, priced as a spread over a short-term reference rate — SOFR, following the retirement of USD LIBOR. That means a CLO's income moves with short-term rates rather than with the level of long-term bond yields, giving the structure very little interest-rate duration but substantial exposure to credit spreads and defaults.

Seniority sets the spread. The AAA tranche pays the narrowest spread because it sits behind the most subordination; each step down the stack, through AA, A, BBB and BB, pays a wider spread in exchange for a thinner cushion of tranches beneath it absorbing losses first.

The equity tranche is different in kind, not just degree. It receives whatever is left after interest on the loans covers interest on every note above it and all fees — an arbitrage between gross loan income and the cost of the debt stack, leveraged by the size of that debt stack relative to equity. It is quoted on modelled cash flows and an internal rate of return, not as a coupon or a yield, while the debt tranches are quoted as a spread and a price relative to par.

Retail funds that hold CLO tranches add another layer: their distributions typically combine interest earned on the underlying notes with realised trading gains and, in some structures, a return of the investor's own capital. The rate a fund pays out and the income it actually earns are not the same number.

How to read one

The first questions to ask of any CLO exposure are structural: where does this tranche sit in the stack, how much subordination sits beneath it, and how far can the underlying portfolio deteriorate before this tranche stops getting paid. Those answers matter more than the headline spread.

The trustee report carries the working detail — the CCC-rated bucket limit, weighted average rating factor, weighted average spread, weighted average life and diversity score — each a covenant meant to keep the manager from concentrating risk in ways the original tranche pricing did not anticipate.

The manager matters more here than in a static bond portfolio, because during the reinvestment period they choose what to buy and how to respond as individual credits deteriorate. A structured AAA rating describes modelled loss absorption within one specific deal, not the standing of a corporate borrower, and should not be read as equivalent to a AAA corporate bond.

For retail vehicles, the wrapper's name is not a reliable guide to what it actually holds. An AAA-only CLO ETF, a mezzanine-focused fund and an equity-tranche fund can carry entirely different risk profiles under similar branding, and leverage can appear twice — once inside the CLO structure itself, and again at the fund level if a closed-end fund borrows to buy tranches.

Where it goes wrong

The equity tranche is a leveraged first-loss position. In a default cycle its cash flow can fall to nothing while the senior notes above it continue to be paid in full — the structure is designed to protect seniority, not to spread pain evenly.

Coverage-test failures redirect cash upward mechanically. Junior distributions can stop well before any principal has actually been lost in the portfolio, simply because a test tripped; from the junior holder's side this looks identical to a loss even when it is a timing event.

Recovery assumptions do not always hold. Senior secured loans have historically recovered more of their value in default than unsecured debt, but recoveries on covenant-lite loans in recent cycles have run below older historical averages, and a structure priced on past recovery rates can underperform if that pattern continues.

CLOs are frequently confused with the mortgage-backed collateralised debt obligations of 2007 and 2008. The two are related by structure but not by collateral — CLOs hold corporate loans, not subprime mortgage securitisations, and CLO tranches broadly performed through that crisis while mortgage CDOs did not. That is a fact about one cycle, not a guarantee about the next one.

Liquidity is dealer-driven and can thin sharply in stress. CLO fund prices and net asset values can gap when the underlying tranche market stops quoting reliably, which is what happened to CLO-holding funds in March 2020. Complexity compounds this: a tranche's actual economics depend on indenture language most holders never read, and a retail fund wrapper adds a second layer of terms on top of that.

Where you will meet it on this site

CLOs appear on the private credit page as the securitised, publicly tradable end of the corporate lending market, in contrast with directly originated private loans. They appear again on the bond pages, where floating-rate structured credit sits next to fixed-rate corporate debt with a very different sensitivity to interest rates.

Closed-end fund and ETF pages are where these exposures actually reach a brokerage account, since almost no individual investor buys a CLO tranche directly. The credit ratings discussion revisits CLOs as a case where structured and corporate grades share the same letters without sharing the same meaning, and the leveraged loan and business development company pages describe adjacent ways of lending to broadly the same pool of below-investment-grade corporate borrowers.