Any mutual insurance company organized under the laws of this state may create not more than one guaranty fund by borrowing a sum of money not exceeding $500,000, by the issue of certificates of indebtedness upon such terms as the policyholders shall determine provided that such certificates shall not be divided into classes in any way and that the holders of such certificates shall not be entitled to vote in the direction of the affairs of the company and shall not receive a greater return on their investment than 10 percent per annum. The commissioner, upon notice to the company and after hearing its objections, if any, may require any guaranty fund established under this section to be retired when he shall find it is no longer needed for protection of the policyholders.