Conflicts of interest at law firms: the eight rules of Article 12 of the Code of Ethics
Conflict of interest is one of the most relevant ethical risks for a firm with many clients. The Code of Ethics of the Spanish Legal Profession devotes eight rules to it in its Article 12, and the last extends all the others to the firm as a whole.
The more a firm grows, the more likely it is that two of its clients end up on opposite sides, or that a new client wants to act against a former one. The Code of Ethics of the Spanish Legal Profession, approved by the Plenary of the General Council of the Spanish Legal Profession on 6 March 2019, regulates these situations in section C of its Article 12.
We review its eight rules and what they imply for a firm's organisation.
The general rule
Section C.1 prohibits defending or advising interests opposed to those of other clients whom one is or has been defending or advising, or to the lawyer's own interests. The Code presents loyalty to the client as the fundamental principle in this area.
The eight rules
| Section | Situation | Rule |
|---|---|---|
| C.1 | Opposing interests | Prohibited to defend or advise them, including against one's own interests |
| C.2 | Conflict between two or more clients | Withdraw from defending or advising all of them, unless all those affected expressly authorise |
| C.3 | Intermediation and drafting contracts | May act for all parties, with strict objectivity |
| C.4 | Former client | Do not accept engagements against them if there is a risk to the secrecy of their information or the new client could benefit from it. Never in the same proceeding or its incidents, appeals or enforcement |
| C.5 | Family by mutual agreement | Whoever defended both parties cannot later act for one against the other in the resulting steps, unless they acted for only one with the other's consent |
| C.6 | Several clients in the same situation | Prohibited if a conflict arises between them, there is a risk to secrecy or independence is endangered |
| C.7 | Prior consultation by the other side or a colleague | Do not accept the engagement if in that consultation information was obtained that compromises independence, secrecy or loyalty |
| C.8 | Collective firms | The rules apply to the group as a whole and to each member, whatever the associative form |
The rule that most affects firms: section C.8
Section C.8 is what turns conflict of interest into a matter of organisation. The previous rules do not apply only to the lawyer handling the matter, but to the whole firm, whatever its form: professional company, lawyers' association or collaboration.
That means a firm cannot resolve a conflict by assigning each client to a different team. If the firm, as a group, has a conflict, each of its members has it.
For a firm organised as a professional company, the rule adds to the corporate obligations we review in the guide to the professional law firm company.
The former client: the most delicate case
Section C.4 does not always prohibit acting against a former client. It requires assessing the risk: if there is the possibility of breaching the secrecy of the information obtained, or of the new client benefiting from it, the engagement cannot be accepted. The Code says that the type of matters and the time elapsed are weighed.
What is absolute is the prohibition on acting against the former client in the same proceeding in which they were defended, or in its incidents, appeals, enforcement or derived proceedings.
The connection with professional secrecy is direct, as we explain in the editorial on professional secrecy and client documents.
The prior consultation
Section C.7 covers a situation that can occur at any firm: the other party, or a colleague, consults the firm before the client hires it. If in that consultation information was obtained that puts independence, secrecy or loyalty at risk, the firm cannot later accept the other party's engagement.
How to organise prevention
- A database of clients and opposing parties for all matters, current and past, across the whole firm.
- A check before accepting any engagement or consultation, including initial consultations.
- A record of prior consultations that do not end in an engagement, because of the risk in section C.7.
- Express written authorisations when the exceptions in section C.2 apply.
- Coordination with money laundering prevention, because client identification serves both purposes, as we explain in the guide to anti-money laundering at law firms.
More analysis in Big law firms and lateral moves.
Fuentes
- Consejo General de la Abogacía Española. Código Deontológico de la Abogacía Española, aprobado por el Pleno el 6 de marzo de 2019 (PDF). Accessed 18 October 2026.
The specific data in this article come from the official sources cited.
