There is a CA corp for Cornerstone Investments – registered to HOOSHIAR MAX SAEDI in Laguna Niguel.
There are 12 registries for corporations that have “Cornerstone” and “Investments” in their name. None based in San Diego.
There’s a cancelled LLC based in San Diego: Cornerston Capital Investments (entity #200307710030)
There are 16 LLC’s registered in Ca with Cornerstone and Investments in their name.
There are 422 LLCs registered with the word cornerstone in their name. There are 1113 corporations registered in CA with the words Cornerstone in their name. I did not click through all of them.