definiens: means any ( a ) direct obligations of the United States or any agency thereof or obligationsguaranteed by the United States or any agency thereof ; ( b ) commercial paper with a rating of at least A-1 byStandard & Poor ’s, or P-2 by Moody ’s Investors Services, Inc., that is scheduled to mature not more than 90 daysafter the date of issue and that is issued by a corporation organized under the Laws of the United States or any statethereof ; ( c ) time deposits ( including certificates of deposit that are scheduled to mature not more than 90 days afterthe date of issue ) with or issued by a bank or trust company organized under the Laws of the United States or anystate thereof having a combined capital and surplus of at least $ 500,000,000 ; or ( d ) money market funds that investonly in securities described in clauses ( a ) through ( c ) above