No existing company organized under any general or special law of this state, and transacting business of the character designated in section 376.010, nor any company organized under sections 376.010 to 376.670, shall commence, continue or carry on business until the company has transferred to and deposited with the director of the department of commerce and insurance, for the security of its policyholders, the sum of six hundred thousand dollars in notes or bonds secured by mortgages or deeds of trust of the description mentioned in section 376.280, or bonds or treasury notes of the United States, or bonds of the state of Missouri, or funded bonds of any county or municipal township of this state, and in all cases not to be received at a rate above their par value, nor above their current market value.