definiens: shall mean ( a ) securities issued or directly and fully guaranteed or insured by the United Statesgovernment or any agency or instrumentality thereof having maturities not exceeding six ( 6 ) months from the date ofacquisition, ( b ) certificates of deposit with maturities of six ( 6 ) months or less from the date of acquisition, bankers’acceptances with maturities not exceeding six ( 6 ) months and overnight bank deposits, in each case with any commercial bankorganized and in existence under the laws of the United States and having capital and surplus in excess of $ 500 million, ( c)repurchase obligations with a term of not more than seven ( 7 ) calendar days for underlying securities of the types described inclauses ( a ) and ( b ) above entered into with any financial institution meeting the qualifications specified in clause ( b ) above,(d ) commercial paper having the highest rating obtainable from Moody ’s Investors Service, Inc. or Standard & Poor ’s RatingsServices and in each case maturing within one hundred eighty ( 180 ) calendar days after the date of acquisition, ( e)investments in commercial paper, maturing not more than one hundred eighty ( 180 ) calendar days after the date ofacquisition, issued by a corporation organized and in existence under the laws of the United States, or any foreign countryrecognized by the United States, with a rating at the time as of which any investment therein is made of ( or higher)according to Moody ’s Investor 3Service, Inc. or ( or higher ) according to Standard & Poor ’s Ratings Services, and ( f ) money market mutual fundssubstantially all of the assets of which are of the type described in the foregoing clauses ( a ) through ( e ) above