... Federal National Mortgage Assoc. 40,239,307 Aaa AAA 7.73 Federal Home Loan Mortgage Corp. 30,208,734 Aaa AAA 0.42 $144,881,167 U. S. Treasury $6,293,938 NA NA ... statements contain estimates for Arbitrage Rebate Liability and Allowance for Loan Losses. Capital Assets: Capital assets are recorded at cost and depreciation is computed using the straight-line ... service. Vacation leave may be accumulated to a total not to exceed two times the maximum number of days earned annually. Sick leave is earned at the rate of 12 days per year with no limit on accumulation....