related unrealized gains and losses included in accumulated other comprehensive income, a component of stockholders’ equity, net of tax.



As of January 29, 2012 and January 30, 2011, we had $3.13 billion and $2.49 billion, respectively, in cash, cash equivalents and marketable securities.  Our investment policy requires the purchase of top-tier investment grade securities, the diversification of asset types and includes certain limits on our portfolio duration, as specified in our investment policy guidelines. These guidelines also limit the amount of credit exposure to any one issue, issuer or type of instrument. As of January 29, 2012, we were in compliance with our investment policy.  As of January 29, 2012, our investments in U.S. government agencies and U.S. government sponsore enterprises represented approximately 51% of our total investment portfolio, while the financial sector accounted for approximately 24% of our total investment portfolio. All of our investments are with A/A2 or better rated securities.



We performed an impairment review of our investment portfolio as of January 29, 2012.  Based on our quarterly impairment review, we concluded that our investments were appropriately valued and did not record any impairment during fiscal year 2012.    In the fourth quarter of fiscal year 2011 we recovered $3.1 million of the other than temporary impairment charge previously recorded.  This was recorded as other income in fiscal year 2011.  



Net realized gains, excluding any impairment charges, were $0.4 million, $1.5 million and $1.8 million for fiscal years 2012, 2011 and 2010 respectively.  As of January 29, 2012, we had a net unrealized gain of $11.5 million, which was comprised of gross unrealized gains of $12.0 million, offset by $0.5 million of gross unrealized losses.  As of January 30, 2011, we had a net unrealized gain of $10.5 million, which was comprised of gross unrealized gains of $11.0 million, offset by $0.5 million of gross unrealized losses. 



Our accounts receivable are highly concentrated and make us vulnerable to adverse changes in our customers’ businesses, and to downturns in the industry and the worldwide economy.  Two customers accounted for approximately 27% of our accounts receivable balance at January 29, 2012. While we strive to limit our exposure to uncollectible accounts receivable using a combination of credit insurance and letters of credit, difficulties in collecting accounts receivable could materially and adversely affect our financial condition and results of operations. These difficulties are heightened during periods when economic conditions worsen. We continue to work directly with more foreign customers and it may be difficult to collect accounts receivable from them. We maintain an allowance for doubtful accounts for estimated losses resulting from the inability of our customers to make required payments. This allowance consists of an amount identified for specific customers and an amount based on overall estimated exposure. If the financial condition of our customers were to deteriorate, resulting in an impairment in their ability to make payments, additional allowances may be