Short answer. Yes. When people who never organized as a juridical entity enter into a transaction, they may still be sued under the name they are commonly known by. Once sued, they have to reveal, in their answer, the actual names and addresses of everyone behind the business.
What the law says
When two or more persons not organized as an entity with juridical personality enter into a transaction, they may be sued under the name by which they are generally or commonly known. In the answer of such defendant, the names and addresses of the persons composing said entity must all be revealed.
Rule 3, Section 15 — Entity without juridical personality as defendant. Read the full provision →
The absence of registration is not a shield
A business that never incorporated or registered as a partnership does not thereby become un-suable. The rule lets a plaintiff sue people who are not organized as an entity with juridical personality using the name by which they are generally or commonly known — the trade name or shop name the public actually associates with the business, even though it has no formal legal existence of its own. The rule exists precisely because unregistered arrangements are common, and a plaintiff should not be left without a defendant to name simply because the people behind a business skipped registration. It applies whether the arrangement is two people running a stall or a larger group operating under one shared name.
The defendant has to name names in the answer
Once such a defendant is sued and files its answer, the rule requires it to reveal the names and addresses of the persons composing said entity. This is what ultimately lets the plaintiff identify and, if necessary, pursue the actual individuals behind the business name, rather than being stuck litigating against a name with no one clearly accountable behind it. The disclosure is not optional once the defendant has been sued under the common name it operates under.
Why this matters to someone with a claim
Many small businesses operate under a trade name without ever formally registering as a corporation or partnership, and a customer, supplier, or other party dealing with them may have no way of knowing the identities of the people actually running it. This rule means the absence of formal registration does not leave that party without a way to sue — the case can proceed against the business as commonly known, with the individuals' identities surfacing through the litigation itself. That sequence matters for anyone trying to recover from a business that has no formal registration on record anywhere, since it removes the excuse that no proper defendant can be named.