The life insurance department of a savings bank may invest in the capital stock, capital notes and debentures of a savings banks trust company or service agency, provided the aggregate amount of its investments in such stock, notes and debentures, including the proposed investment, would not exceed the greater of two percent of the sum of its policy reserves and policy liabilities or $20,000. The term policy reserves and policy liabilities shall have the meaning specified in Banking Law, section 275.