Contingent convertible bonds absorb bank losses through mandatory conversion or principal write-down when specified capital or non-viability triggers occur.
Contingent convertible bonds (CoCos) are loss-absorbing capital securities, most often issued by banks, that respond to a specified capital or non-viability trigger. Depending on the governing terms and regulatory framework, a triggered instrument may convert into common equity or have its principal written down temporarily or permanently.
A CoCo is not simply a conventional convertible bond with extra upside. The holder generally does not choose conversion because the share price looks attractive. Loss absorption is mandatory when the applicable trigger or authority decision operates, often while the issuing bank is under severe stress.
| Feature | What can happen | What to verify |
|---|---|---|
| Mechanical capital trigger | A stated regulatory ratio falls through a contractual threshold | Ratio definition, calculation date, group level, and threshold |
| Point-of-non-viability trigger | A relevant authority determines that write-off or conversion is necessary | Authority, statutory basis, contractual language, and timing |
| Equity conversion | Principal converts into a stated or formula-based number of shares | Conversion price, cap, floor, dilution, and share issuer |
| Permanent write-down | Some or all principal is extinguished | Write-down amount, ranking, and whether any claim remains |
| Temporary write-down | Principal is reduced and may later be written up | Write-up conditions, limits, discretion, and payment priority |
Do not infer the outcome from the word “convertible.” Some instruments absorb losses without issuing equity, and some frameworks can apply more than one trigger. The disclosure should also state whether conversion or write-down is full or partial.
Assume a bank has $100 billion of risk-weighted assets and $8.2 billion of CET1 capital, producing an 8.2% CET1 ratio. A hypothetical CoCo has a contractual trigger below 7%. If losses reduce CET1 capital to $6.8 billion while risk-weighted assets remain $100 billion, the ratio falls to 6.8% and crosses the stated trigger.
Consider three possible terms for a holder with $1,000 principal:
| Hypothetical loss-absorption term | Holder outcome immediately after trigger |
|---|---|
| Convert at $5 per share | Receive 200 shares; if shares then trade at $3, market value is $600 |
| Permanent 60% write-down | Principal claim falls from $1,000 to $400 |
| Temporary 60% write-down | Principal falls to $400, with any later write-up dependent on the exact terms |
The example isolates the mechanism; it is not a recovery forecast. In practice, risk-weighted assets can change at the same time as capital, the trigger calculation may use transitional adjustments, and the share price can continue falling after conversion. A temporary write-down is not equivalent to guaranteed restoration, and a conversion is not equivalent to repayment at par.
| Question | Conventional convertible bond | Contingent convertible bond |
|---|---|---|
| Why conversion occurs | Usually holder election under stated terms | Usually mandatory capital or non-viability trigger |
| Typical investor motive | Debt income plus potential equity participation | Income in exchange for bank capital loss-absorption risk |
| Likely conversion setting | Share price makes conversion valuable | Issuer is under capital or viability stress |
| Alternative to conversion | Continue holding debt, subject to terms | Principal may instead be written down |
| Main analytical focus | Conversion value, premium, credit, and dilution | Trigger, write-down, coupon, call, seniority, and resolution |
See Convertible Bond for the conventional holder-option structure.
Many bank CoCos are structured to qualify as Additional Tier 1 capital, but not every CoCo has the same regulatory classification. Under the Basel criteria, an Additional Tier 1 instrument is perpetual and may be called by the issuer only after the minimum period and with prior supervisory approval, subject to further capital conditions.
Investors should therefore model both call and no-call outcomes. If the instrument is not called, its coupon may reset under the stated formula, but principal does not become due merely because the first call date passes. Market price can fall if investors had expected redemption.
The Basel Committee’s Definition of Capital sets out Additional Tier 1 criteria, including perpetuity, call restrictions, coupon discretion, and principal loss absorption. Its capital-instrument disclosure requirements distinguish full or partial conversion, permanent or temporary write-down, trigger terms, and conversion rates. The BIS Basel III capital summary explains the role of going-concern and point-of-non-viability loss absorption.
These sources describe the international framework. Security-specific analysis requires the current prospectus, capital disclosure, issuer filings, national rules, and resolution law. This page is educational only and is not investment, legal, tax, or regulatory advice.