The following table presents the Moody's and Standard & Poor's ratings of our debt securities portfolio:
our investment portfolio represented less than 1%, with an amortized cost of $14.7 million and a fair value of $13.3 million. The unrealized loss on these securities represented 5% of our total unrealized loss at December 31, 2003, and 10% at December 31, 2002. The fair value of these securities was determined by independent pricing services or bid prices provided by various broker dealers. The Company did not have a material investment in non-traded securities in 2003 or 2002.
In addition to the cash requirements of the Parent, our operating obligations and cash outflows include: claim settlements; commissions; labor costs; premium taxes; general and administrative expenses; investment purchases; and capital expenditures. The Insurance Subsidiaries also have additional investment commitments for their limited partnership investments of up to $32.4 million; however, there is no certainty that any additional investment will be required. The Insurance Subsidiaries satisfy their obligations and cash outflows through premium collections, interest and dividend income and maturities of investments.
Financial instruments that could potentially subject the Company to concentration of credit risk include accounts receivable associated with our human resource administration outsourcing subsidiary, which acts as a co-employer with certain clients. As a co-employer, we contractually assume substantial employer rights, responsibilities and risks of our clients' employees, who are considered co-employees. These accounts receivable, which are included in other trade receivables on the consolidated balance sheets, consist of service fees to be paid by our clients. Under the accrual method, earned but unpaid wages at the end of each period related to the Company's worksite employees are recognized as an accrued payroll liability as well as an account receivable during the period in which wages are earned by the worksite employee. Subsequent to the end of each period, such wages are paid and the related co-employer service fees are billed. Accrued co-employer payroll and related service fees were $15.5 million as of December 31, 2003 and $12.2 million as of December 31, 2002. Certain states limit a co-employer's liability for earned payroll to minimum wage. This would reduce the Company's potential liability for accrued co-employer payroll. In the event that a client does not pay their related payroll and service fees prior to the applicable payroll date, the Company has the right to cancel the co-employer contract or at its option, require letters of credit or other collateral. The Company has generally not required such collateral. As of December 31, 2003 the maximum exposure to any one account for earned payroll is approximately $1.2 million. If the financial condition of a client were to deteriorate rapidly, resulting in nonpayment, the Company's accounts receivable balances could grow and the Company could be required to provide for allowances, which would decrease net income in the period that such determination was made.
The value of real estate, furniture and equipment is stated at cost less accumulated depreciation. Provisions for depreciation are computed using the straight-line method over the estimated useful lives of the assets, which range from two to forty years for financial statement purposes and the straight-line method and various accelerated methods for federal income tax purposes. The Company capitalizes the costs of computer software developed or obtained for internal use and amortizes the cost using the straight-line method over estimated useful lives of the systems being developed that range from three to ten years.
For the 8.87% Senior Notes, the Company is required to pay $12.3 million principal amount in each year commencing on May 4, 2006 and ending on May 4, 2010, inclusive, together with accrued interest thereon. The unpaid principal amount of these Senior Notes accrues interest and is payable semiannually on May 4 and November 4 of each year, until the principal is paid in full.
The Company has revolving lines of credit with State Street Corporation, $20.0 million, and Wachovia Bank, $25.0 million, totaling $45.0 million at December 31, 2003. The lines of credit in 2002 were $25.0 million for State Street Corporation, and $25.0 million for Wachovia Bank, totaling $50.0 million. At December 31, 2003 and 2002, there were no balances outstanding. Interest is determined on a LIBOR, prime rate or money market rate basis at the Company's option. The weighted average interest rate on these borrowings was 1.67% in 2003. No borrowings were made during 2002.
All amounts in the reconciliations of funded status were recognized in the consolidated balance sheets for 2003 and 2002. There were no amounts to be included in other comprehensive income for the periods shown resulting from a change in the minimum pension liability. The Company presently anticipates contributing $7.9 million to the retirement income plan in 2004.
Our investment objective is to maximize total return while preserving capital to meet plan obligations.
2. See Note 13 to the consolidated financial statements and Financial Review for a discussion of discontinued operations.