6. Accounts receivable reserve

In evaluating the net realizable value of accounts receivable, the Company considers such factors as current economic trends, customer credit-worthiness, and changes in the customer payment terms and collection trends. Changes in the assumptions used in analyzing a specific account receivable may result in a reserve being recognized in the period in which the change occurs.

Changes in the reserves against current billed accounts receivable were as follows (in thousands):

At September 30, 2012 and 2011, $3.2 million and $4.2 million of our billed receivables related to amounts pursuant to contractual retainage provisions. We anticipate that the majority of the fiscal 2012 balance will be collected during the 2013 fiscal year.