To enable it to determine whether it will issue the order, the commission may hold a hearing and may make such additional inquiry or investigation, examine such witnesses, books, papers, documents, and contracts, and require the filing of such data as it deems of assistance. The commission may by its order grant permission for the issue of such stocks or stock certificates or other evidence of interest or ownership, or bonds, notes, or other evidences of indebtedness in the amount applied for, or in a lesser amount, or refuse such permission, or grant it subject to such conditions as it deems reasonable and necessary. The commission may authorize issues of bonds, notes, or other evidences of indebtedness, less than, equivalent to or greater than the authorized or subscribed capital stock of a public utility corporation.