For example,
Claims are not liable to insurers, investors, nor S Corporation and its owners.
Claims are not liable to insurers, investors, S Corporation, nor its owners.
Which conjunction would you use?
For example,
Claims are not liable to insurers, investors, nor S Corporation and its owners.
Claims are not liable to insurers, investors, S Corporation, nor its owners.
Which conjunction would you use?
Both are correct, the presence of a pronoun is irrelevant.
In the first list you have three categories who are not liable to claims:
In the second case you have four categories
If you want the owners to be seen as a different category from the corporation (if, for example, you could sue the owners but not the corporation) then use the second. If not, (if the owners are merely the human face of the corporation) then use the first.
First of all, your first example is incorrect as a list can only have one conjunction.
To answer your question, 'or' is the correct conjunction. 'And' is not applicable because this list is about something that does not happen, and 'nor' is only used after 'neither' as in:
Neither John nor Bob wanted to go to the supermarket.
Therefore, your sentence should look like this:
Claims are not liable to insurers, investors, S Corporation, or its owners.
The question is idiotic. “Claims” are assertions of legal (or moral) rights. “Liable to” indicates a legal (or moral) obligation. A liability results from a claim being vindicated. (Lambie pointed this out months ago.) Liability is a result of claims rather than being a beneficiary of claims.
Linguistically, the listing is flawed. The exemplars could be listed as singulars:
an insurer, an investor [with limited liability?], an S corporation, or any of its owners jointly or singly.
Alternatively, they could be listed as categories with multiple members:
insurers, investors [with limited liability?, S corporations, or their owner or owners
An S corporation may have more than one owner, and, if so, they can be identified as “its” owners, indicating that only one corporation is involved.
More than one S corporation may share a single owner, or several S corporation may each have a single owner, or several S corporations may share a common group of owners, or other variations. Trying to list exhaustively all the potential relations between corporations and owners risks leaving one out. Consequently, it is clearer to go with the singular version
an S corporation or any of its owners singly or jointly.
Of course, it is dubious why an S corporation is treated differently from other legal forms enjoying limited liability.
an insurer, a creditor, or anyone holding an equity interest protected by limited liability.
People mock and disparage the verbosity of legal writing, but it arises out of a need to be correct and complete.