This excerpt taken from the TTEK 10-K filed Dec 28, 2006.
Concentration of Credit RiskFinancial instruments, which subject the Company to credit risk, consist primarily of cash and cash equivalents and net accounts receivable. The Company places its temporary cash investments with high credit quality financial institutions and, by policy, limits the amount of investment exposure to any one financial institution. Approximately 36% and 32% of accounts receivable was due from various agencies of the federal government as of October 1, 2006 and October 2, 2005, respectively. The remaining accounts receivable are generally diversified due to the large number of organizations comprising the Companys client base and their geographic dispersion. The Company performs ongoing credit evaluations of its clients and maintains an allowance for potential credit losses.