INVESTMENTS

Equity Investments

The following table summarizes the company's equity investments as of October 31, 2015 and 2014 (net book value):



	October 31,
	2015		2014
	(in millions)
Long-Term
Cost method investments	$	17	$	15
Trading securities	12		13
Available-for-sale investments	41		35
Total	$	70	$	63

Cost method investments consist of non-marketable equity securities and one fund and are accounted for at historical cost. Trading securities are reported at fair value, with gains or losses resulting from changes in fair value recognized currently in earnings. Investments designated as available-for-sale are reported at fair value, with unrealized gains and losses, net of tax, included in stockholders' equity.

In June 2015, we purchased $7 million of preferred stock of a privately held radio frequency microstructure company. We

are accounting for this investment using the cost method.

Investments in available-for-sale securities at estimated fair value were as follows:



	October 31, 2015								October 31, 2014
	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
	(in millions)
Equity securities	$	15	$	26	$	—	$	41	$	15	$	20	$	—	$	35

All of our investments, excluding trading securities, are subject to periodic impairment review. The impairment analysis requires significant judgment to identify events or circumstances that would likely have a significant adverse effect on the future value of the investment. We consider various factors in determining whether an impairment is other-than-temporary, including the severity and duration of the impairment, forecasted recovery, the financial condition and near-term prospects of the investee, and our ability and intent to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value. In 2015, other cost method investments with a carrying amount of $4 million were written down to their fair value of zero, resulting in an impairment charge of $4 million, which is included in other income (expense), net. There were no impairments recognized in 2014 and 2013.

There were no realized gains on the sale of available-for-sale securities in 2015, 2014 and 2013. Net unrealized gains and losses on our trading securities portfolio were $1 million of unrealized gains in 2015, $1 million of unrealized gains in 2014 and $2 million of unrealized gains in 2013. Realized gains from the sale of cost method securities was zero for 2015, 2014 and 2013.