An industrial loan company that has investment certificates outstanding shall not make loans to, or hold the obligations of, any one person as primary obligor in an aggregate principal amount in excess of 20 percent of the unimpaired capital stock and surplus of the company not available for dividends as provided in Section 18319. Unsecured loans or obligations of any person as primary obligor made or held by a company may not, in any event, exceed in the aggregate principal amount 5 percent of the unimpaired capital stock and surplus of the company not available for dividends as provided in Section 18319.