The Securities and Exchange Commission wants to hear from publicly traded companies, their investors, and others on how its proxy plumbing is functioning.

Proxy plumbing is the system behind how companies communicate with investors via proxy statements and how investors weigh in on company matters through proxy voting. The SEC is holding a roundtable this fall to get feedback on its proxy-related rules.

The roundtable, announced July 30 by SEC Chairman Jay Clayton, doesn’t have a set agenda or date yet. Topics for discussion include the process for casting and counting shareholder votes on everything from executive pay to mergers,...