A cash flow waterfall is the fixed order in which money collected from a securitised pool is paid out. Fees and costs are paid first, then interest to the senior tranche, then interest to junior tranches, then principal, and whatever remains flows to the equity holder. The order decides who absorbs losses and who is protected from them.
Key Takeaways
- A waterfall is a priority of payments written into the deal documents, and every rupee collected from the pool follows it.
- Senior investors are paid first and absorb losses last, which is why they accept a lower return.
- Most deals run separate interest and principal waterfalls, and many switch from pro rata to sequential payment when performance weakens.
- Triggers such as overcollateralisation and interest coverage tests redirect cash to protect senior investors automatically.
- ABSO (Asset Backed Securitisation Orchestration) models the waterfall on the same record as the loan data and encodes it as a smart contract, so coupon and principal are paid by rule and every party sees where each payment went.
What Is A Cash Flow Waterfall
In a securitisation, a lender sells a pool of loans to a special purpose vehicle, and the vehicle issues securities to investors. Borrowers keep paying interest and principal every month. The waterfall is the rulebook that decides how those collections are shared out.
It is called a waterfall because cash fills the first level of obligations before any of it spills to the next. A tranche lower down the order is only paid once every tranche above it has received what it is owed for that period.
The waterfall is set in the transaction documents before the deal closes. The trustee applies it, the servicer supplies the collections, and investors rely on it when they price each tranche. Its design is one of the main things a rating agency tests.
Who Runs The Waterfall Each Month
The servicer collects from borrowers and reports what came in, loan by loan. A calculation agent, often the trustee, applies the waterfall to those collections and works out what each party is owed. The trustee then instructs the payments and reports to investors.
Every step depends on the servicer data being right. If the collections report is late or wrong, the whole payment date slips or has to be corrected later, which is why investors ask for loan-level data as well as pool totals. This is the gap ABSO closes: loan-wise servicing data stays attached to the pool for the life of the deal, so the calculation runs on the same figures every party can see.
How Does A Cash Flow Waterfall Work, Step By Step
A typical monthly waterfall in a loan securitisation runs in this order. The exact steps differ from deal to deal, but the logic is the same everywhere.
- Senior costs. Taxes, trustee fees, servicing fees and any other deal expenses are paid first.
- Senior interest. The senior tranche, often called Class A, receives the interest due for the period.
- Junior interest. The mezzanine tranche receives its interest, followed by any further junior classes in order.
- Principal. Principal collected from borrowers is paid to the tranches, usually the senior tranche first.
- Reserve top-up. If a cash reserve or liquidity account has been drawn on, it is refilled to its required level.
- Residual. Anything left, known as excess spread, goes to the equity holder, who is often the originator.
Many deals keep an interest waterfall and a principal waterfall as two separate pots. Interest collections pay fees and coupons, while principal collections pay down the notes. Keeping them apart stops principal being used to cover a shortfall in interest unless the documents allow it.
In ABSO this sequence is encoded as a smart contract once the deal closes, so each payment date follows the agreed priority without a spreadsheet rebuilt by hand.
A Worked Example Of A Securitisation Waterfall
Take an illustrative pool of 1,240 loans worth ₹412 crore, structured into three classes: Class A at 62%, a mezzanine class at 26% and an equity piece at 12%. Assume the pool collects ₹10 crore in one month, made up of ₹3.2 crore of interest and ₹6.8 crore of principal.
| Step | Paid To | Amount (₹ Crore) | Cash Left (₹ Crore) |
|---|---|---|---|
| Collections for the month | Into the collection account | 10.00 | 10.00 |
| Senior costs | Trustee and servicer fees | 0.20 | 9.80 |
| Senior interest | Class A at 6.4% a year | 1.36 | 8.44 |
| Junior interest | Mezzanine at 8.9% a year | 0.79 | 7.65 |
| Principal | Class A, paid sequentially | 6.80 | 0.85 |
| Residual | Equity holder as excess spread | 0.85 | 0.00 |
These figures are illustrative. The point is the order. If collections fell short, the equity holder would lose its residual first, then the mezzanine class would miss interest, and Class A would be the last to feel any loss. That protection is why Class A carries the lowest coupon. The guide to senior, mezzanine and equity tranches explains how each class is sized.
ABSO runs this kind of calculation on the actual pool instead of a copy of it, so a change to a coupon or a class size is tested against real loan data before issuance.
Sequential Vs Pro Rata Payment
Under sequential payment, all principal goes to the most senior tranche until it is fully repaid, then to the next. Senior investors are repaid quickly and their protection grows over time, because the junior tranches become a larger share of what remains.
Under pro rata payment, principal is shared across tranches in proportion to their size. Junior investors get their money back sooner and the deal is cheaper for the originator, but the protection for senior investors stays flat.
Many deals start pro rata and switch to sequential if performance deteriorates. The switch is set by triggers written into the waterfall, so it happens by rule and needs no negotiation when the pool comes under stress. In ABSO the issuer can compare both payment modes against the same pool before the structure is fixed.
Triggers That Redirect Cash In A Waterfall
Triggers are tests run every payment date. When one fails, the waterfall changes shape to protect the senior investors.
- Overcollateralisation test. Checks that the pool balance stays above the balance of the notes by a set margin. If it falls below, cash that would have gone to equity is diverted to pay down senior notes.
- Interest coverage test. Checks that interest collected comfortably covers the interest owed. A failure traps excess cash inside the deal.
- Delinquency and loss triggers. Measure arrears and cumulative losses against agreed limits, and can switch principal to sequential payment.
- Reserve account rules. Set the size of a cash reserve and the order in which it is drawn and refilled.
The design choices here drive the deal economics. Loose triggers make the equity piece more valuable. Tight triggers make the senior tranche safer and cheaper to fund.
How ABSO Enforces The Cash Flow Waterfall
ABSO, the securitisation and pool structuring platform, models the tranches and the waterfall on the same record that holds the loan data. The pool starts clean when the loans were originated in LOA (Loan Origination Assistant), because those files flow into ABSO for pooling with ASF tapes and pool extractions generated from the same record.
- Structuring. ABSO sets tranches, the waterfall and credit enhancement against the pool, and models enhancement in minutes, to within 1%, so issuers can test combinations quickly.
- Execution. Once the deal is live, the waterfall runs as smart contract policy, so coupon and principal are paid in the agreed order every period.
- Reporting. Trustees, custodians and investors see real-time performance and automated reporting from a permissioned ledger, which removes the monthly reconciliation between spreadsheets.
- Existing operations. Fund administration, NAV, servicing and compliance stay exactly as they are, and ABSO adds the distribution rail on top.
The time from loan tape to issuance runs to 8 to 10 weeks. The wider picture of how pools become funding is covered in how loan pools become liquidity.
See ABSO Run A Waterfall On Your Own Loan Tape
- Book a securitisation waterfall demo with the Istakapaza team.
- Bring a recent loan tape for a pool you plan to fund, together with the structure or term sheet you are considering.
- The demo shows ABSO aggregating that pool, setting the tranches and the waterfall, testing credit enhancement and presenting the investor view of each payment date.
Read more about the ABSO securitisation platform.
Frequently Asked Questions
What is a cash flow waterfall in securitisation?
It is the order in which collections from a securitised pool are paid out. Costs come first, then interest to senior investors, then interest to junior investors, then principal, and any residual goes to the equity holder. The order is fixed in the deal documents and decides who bears losses first.
What is the difference between sequential and pro rata payment?
Sequential payment repays the senior tranche in full before any junior tranche receives principal. Pro rata payment shares principal across tranches by size. Many deals start pro rata and switch to sequential automatically if performance triggers are breached.
Why do waterfalls have triggers?
Triggers protect senior investors when a pool starts to underperform. If a test on overcollateralisation, interest coverage or losses fails, the waterfall diverts cash away from junior classes to pay down or protect the senior notes, without any new negotiation.
Can a cash flow waterfall be automated?
Yes. ABSO, the Istakapaza securitisation platform, encodes the waterfall agreed at closing as a smart contract, so coupon and principal execute by rule each period. Trustees, investors and rating agencies read the same figures from one permissioned record, and loan-wise servicing data stays attached to the pool.
Glossary
- Waterfall
- The priority of payments that governs how collections from a securitised pool are distributed.
- Excess Spread
- Interest earned on the pool minus interest and costs paid on the notes.
- Sequential Payment
- A structure where principal repays the most senior tranche in full before the next.
- Pro Rata Payment
- A structure where principal is shared across tranches in proportion to their size.
- Overcollateralisation
- Holding more pool assets than the value of notes issued, as a buffer against losses.
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