(a) The term security shall mean any stock, or any bond, note, debenture or other evidence of indebtedness. The term security does not include a futures contract or an option or warrant to purchase a security, except that an option or warrant acquired by the thrift institution as part of a unit which includes a debt or equity security shall constitute a security.

(b) The term qualified debt security shall mean any debt security which is not in default as to either principal or interest when acquired.

(c) The term qualified equity security shall mean any equity security which is, at the time of acquisition, listed on the New York Stock Exchange or the American Stock Exchange, or any equity security for which, at the time of acquisition, representative high and low bid prices are regularly quoted on the National Association of Securities Dealers Automated Quotation System.

(d) The term thrift institution shall mean a savings bank or savings and loan association organized under, or subject to the provisions of, the Banking Law.