The Return of a Misunderstood Instrument
Contingent convertible bonds – known in financial circles as CoCos or AT1 bonds – occupy a strange corner of the capital markets. They look like bonds on the surface, pay a coupon like bonds, and trade on exchanges like bonds. But embedded inside each one is a mechanism that can, under specific stress conditions, either convert the instrument into equity or write down its principal entirely. That dual nature made them a fixture of post-2008 bank capital frameworks, and it is making them relevant again now as banks across Europe and parts of Asia quietly rebuild their capital cushions.
The renewed appetite for AT1 issuance follows a period of extreme turbulence. The forced write-down of Credit Suisse’s AT1 bonds during its 2023 collapse sent a jolt through the market – not just because the bonds were wiped out, but because equity holders received something while AT1 holders received nothing, inverting the traditional hierarchy most investors had assumed was inviolable. That episode caused spreads to blow out and issuance to stall for months. What is happening now is a measured return, not a full-blown revival, but it is real enough to warrant attention from fixed-income investors trying to understand what the instrument actually offers.
How CoCos Actually Work
The mechanics of a contingent convertible bond hinge on what the issuing bank’s capital ratios do under pressure. Each AT1 bond is written with a trigger – typically expressed as a Common Equity Tier 1 ratio – below which the conversion or write-down activates. A bank whose CET1 ratio falls below, say, 5.125% would see its outstanding AT1 instruments convert into common shares or simply absorb losses through principal reduction. The exact structure varies by issuer, by jurisdiction, and by the specific terms of each instrument, which means that two CoCo bonds from two different European banks can behave in meaningfully different ways under stress.
This complexity is not incidental to the instrument – it is the point. Regulators designed AT1 bonds to function as a buffer that absorbs losses before taxpayers do, but after regular equity has been tested. The bank gets to classify the coupon payments as interest for accounting purposes while counting the principal toward its regulatory capital requirements. Investors, in exchange for accepting that tail risk, receive a yield premium that can run several hundred basis points above what a senior unsecured bond from the same issuer would pay. That spread represents compensation for the conversion risk, the write-down risk, and the extension risk that comes from the perpetual or very long-dated structure most AT1s carry.
Why Banks Are Coming Back to the Market
Several European banks have returned to the AT1 market in 2024 and into 2025, issuing new instruments at spreads that, while tighter than the panic levels of early 2023, remain elevated enough to attract yield-seeking institutional buyers. The logic driving issuance is straightforward: banks operating under Basel III finalization requirements face ongoing pressure to maintain specific capital ratios, and AT1 bonds remain one of the more efficient tools for doing so without diluting existing equity shareholders by issuing new stock.
For banks specifically, the cost of AT1 capital has to be weighed against alternatives. Issuing common equity is dilutive. Retained earnings take time. Tier 2 subordinated debt counts toward capital but in a different bucket with different limits. AT1 bonds sit in a specific regulatory slot – Additional Tier 1 capital – and they fill it in a way no other instrument exactly replicates. When spreads compress enough that the all-in cost of AT1 issuance becomes manageable against projected returns on equity, banks issue. That calculus is turning favorable again for a number of issuers.
The investor side of this equation is equally interesting. A number of dedicated AT1 funds and credit-focused institutions that backed away from the market after the Credit Suisse shock have quietly rebuilt positions. The argument they make is not that the Credit Suisse write-down was wrong, but that it was exceptional – a function of specific Swiss regulatory decisions made under extreme time pressure – and that the legal frameworks in most other jurisdictions treat AT1 holders differently. That distinction matters enormously when assessing whether the risk premium currently available adequately compensates for actual expected loss.
There is also a broader yield dynamic at play. With rate cycles having moved dramatically over the past three years, investors who once found adequate income in investment-grade corporate bonds are being pushed further out on the risk spectrum. AT1 bonds, which can yield anywhere from 6% to over 9% depending on issuer quality and market conditions, offer income that looks attractive relative to safer alternatives – even after accounting for the discontinuous risk profile that makes them genuinely unlike most fixed-income instruments.
The Risks That Have Not Gone Away
The Credit Suisse episode clarified something that the instrument’s original documentation always stated but that many investors had discounted: the trigger event risk is real, and when it fires, it can wipe out principal entirely. The conversion or write-down mechanism is not a theoretical tail scenario – it is a feature that functions exactly as designed when a bank’s capital falls far enough. Investors who model AT1 bonds purely as high-yield corporate bonds, treating coupon cancellation and conversion as remote and symmetric risks, tend to underprice the actual downside.
Coupon cancellation is a separate and more frequently underappreciated risk. AT1 coupons are discretionary – regulators can instruct a bank to skip payments, and banks themselves can cancel them without triggering a formal default. A bank that is technically solvent but under supervisory pressure may find itself directed to conserve capital by suspending AT1 distributions. That scenario does not wipe out principal, but it can destroy the return profile for investors who bought the bond at a premium expecting reliable income streams.
Who Should Be Looking at This Instrument
AT1 bonds are not retail instruments, and treating them as such carries real danger. The typical buyer is an institutional fixed-income manager, a dedicated bank capital fund, or a sophisticated private credit investor with the analytical capability to model bank balance sheets, read regulatory disclosures, and understand the differences between English-law and Swiss-law AT1 structures. The instrument demands that level of scrutiny because the pricing depends on factors – regulatory intervention risk, specific trigger levels, individual bank capital trajectories – that are not visible in a standard yield-to-maturity calculation.
For institutional investors already allocated to financial sector credit, the current environment offers a genuine opportunity to pick up yield in a segment where the initial shock has faded but spreads have not fully normalized. The banks returning to market now are doing so with cleaner balance sheets and under tighter regulatory oversight than existed before 2023. That does not eliminate the risk of another disorderly write-down event, but it does mean the base case for most current AT1 issuers looks more stable than sentiment alone might suggest.
Reading the Spread Carefully
Spread analysis on AT1 bonds requires more granularity than on standard corporate debt. Two bonds carrying identical ratings from the same agency can have meaningfully different risk profiles depending on whether the write-down mechanism is temporary or permanent, whether the trigger is tied to a point-in-time capital measurement or a regulatory judgment call, and whether the issuer operates in a jurisdiction that has historically respected the capital hierarchy in resolution scenarios. These distinctions show up in pricing if you look carefully enough – a bank whose AT1 bonds trade significantly wider than peers with similar ratings is often signaling something that aggregate credit scores do not capture.
The extension risk on AT1 bonds also deserves more attention than it typically receives. Most AT1s are structured with call dates rather than legal maturities, and while market convention once treated the first call date as effectively the maturity, banks have demonstrated willingness to pass on calls when doing so is economically rational. An investor who bought a perpetual AT1 bond expecting a five-year effective duration can find themselves holding a much longer instrument if rates move or credit conditions shift in ways that make refinancing unattractive for the issuer.
The banks now returning to the AT1 market are betting that investors have processed the Credit Suisse lesson and moved on – that spreads will continue to compress as memory fades and yield hunger intensifies. Whether that compression reflects genuine credit improvement or simply receding fear is the question every buyer of a newly issued AT1 bond is implicitly answering with their capital.
