value is determined to be other than temporary, an impairment charge is recorded and a new cost basis in the investment is established. 

We lend certain fixed-income and equity securities to enhance investment income. The loaned securities continue to be carried as investments on our balance sheet. 

We use derivative instruments to manage exposures to interest rates, equity prices, and foreign currency markets and to facilitate portfolio diversification. Net losses on derivatives were as follows: 

 

 

During fiscal year 2006, we experienced lower net losses on derivatives as compared to fiscal year 2005 primarily due to net gains on non-designated equity derivatives in the current fiscal year as compared to net losses in the prior fiscal year and higher net gains on commodity positions in the current fiscal year driven by increases in the related commodity indices. These gains were partially offset by higher net losses in time value on foreign exchange contracts used to hedge anticipated foreign currency revenues and higher net losses on interest rate derivative contracts. 

The net gains on equity derivatives during fiscal year 2006 are primarily due to changes in the market value of non-designated equity derivatives. Gains and losses arising from non-designated derivatives are economically offset by unrealized losses and gains, respectively, in the underlying equity securities which are recorded as a component of other comprehensive income. Commodity derivatives are held for the purpose of portfolio diversification. Net losses related to foreign currency contracts relate primarily to changes in time value of options used to hedge anticipated foreign currency revenues. Additionally, net gains and losses on foreign exchange contracts include the changes in the fair value of derivatives used as economic hedges. These gains and losses are partially offset economically by unrealized losses and gains, respectively, in the underlying assets which are included in other comprehensive income. 

Net derivative losses in fiscal year 2005 were primarily related to losses on equity derivatives, interest rate derivatives, and foreign currency contracts. During fiscal year 2005, losses related to equity derivatives used to economically hedge against a decline in equity prices were $202 million and losses related to interest rate derivatives were $53 million. These losses were offset by the combination of realized gains on sales of securities and unrealized gains related to increases in the market value of the underlying assets included as a component of other comprehensive income. Net losses related to foreign currency contracts were $53 million, related to changes in time value of options used to hedge anticipated foreign currency revenues and economically hedging foreign currency based investment exposures. Losses related to hedging foreign currency-based investment exposures were offset by unrealized gains in the underlying assets which are included in other comprehensive income. Net losses on derivatives also included gains related to commodity positions used to provide portfolio diversification. Gains on commodity positions were $46 million