Significant risk transfer

A bank must hold capital against the loans it makes — its own money, set aside in case they go wrong. The more risk, the more capital, and capital is the scarcest thing a bank has.

One way to free some up is to sell the loans, which is a securitisation. But banks often do not want to. The loans are to clients they value, and selling them means telling those clients, or losing the relationship.

So instead the bank keeps the loans and sells only the risk. It finds investors willing to promise: if the first losses on this pool occur, we will pay them. Nothing is transferred, no customer is told, no loan moves. What changes is that the bank now holds less risk, and therefore needs less capital.

The catch is that this only works if the regulator agrees. A supervisor has to be satisfied that the risk really has been transferred — that it is significant, not cosmetic. If it says no, the bank has paid for protection and received no capital benefit at all.

How the risk moves without the loans

Through a guarantee or a credit derivative referencing a defined pool. The investor takes a tranche of the losses — typically the first slice, which is where most of the capital requirement sits. It posts cash as collateral, so the bank is not relying on the investor's own creditworthiness.

That last detail is what makes the structure work after earlier crises taught the market not to rely on unfunded protection from a counterparty that might not be there.

Why the junior tranche

Capital rules charge disproportionately for the riskiest slice of a portfolio. Transferring a relatively thin junior piece removes a large share of the requirement, which is why these trades are efficient. The bank keeps the senior risk, which is cheap to hold.

What the supervisor asks

• Is the transfer genuine and significant, on prescribed tests?
• Does the bank retain any hidden obligation to support the pool?
• Are the maturities aligned, so protection does not expire before the loans?
• Is the pricing consistent with genuine risk transfer rather than a fee arrangement?

What the investor gets

Exposure to a pool of loans made by a bank that is retaining the senior risk and keeping its own money at stake — which is a genuine alignment. Returns are high because the risk is concentrated in the first-loss piece and because the buyer base is small.

The argument for it

Banks are constrained by capital, not by willingness. A mechanism that lets a bank recycle capital while keeping its client relationships means more lending from the same balance sheet. The risk moves to investors who chose it, with their own money, funded in cash — which is a better place for it than an implicit government guarantee.

The argument against it

Risk that leaves the regulated banking system goes somewhere less visible. If the buyers are themselves leveraged, the risk has been transformed rather than removed. And capital relief that reflects a modelling boundary rather than a real change in exposure is optimisation, not risk management.

Supervisors have addressed both by tightening the tests, examining who the buyers are and how they are funded, and requiring disclosure. The debate is live and well-informed on both sides; this page describes it rather than settling it.

Why the buyer base is the structural weakness

Protection on the junior tranche of a bank loan portfolio is bought by a narrow group of specialist funds. If those funds face redemptions, the market closes quickly and banks that had been recycling capital cannot. That is a concentration risk in the mechanism itself rather than in any individual trade.

The distinction that matters

This is not a securitisation, and confusing the two is the commonest error. There, assets are sold, the buyer owns them and the true sale is everything. Here, nothing is sold, the bank still owns the loans and still collects the payments, and the whole transaction is a contract about who bears losses. One is a transfer of assets; the other is a transfer of outcomes.

The formulas above are standard textbook formulations, simplified for teaching. They explain the mechanism — they are not a valuation tool, and they will not reproduce a dealer’s price.