Investment and derivative contract gains/losses in the third quarter and first nine months of 2021 and 2020 are summarized as follows (in millions).

	Third Quarter						First Nine Months
	2021			2020			2021			2020
Investment gains (losses):
Equity securities:
Change in unrealized investment gains (losses) during the period on securities held at the end of the period	$	4,759		$	30,837		$	36,163		$	16,458
Investment gains (losses) on securities sold during the period		75			1,330			889			(13,901	)
		4,834			32,167			37,052			2,557
Fixed maturity securities:
Gross realized gains		24			12			59			53
Gross realized losses		(7	)		(2	)		(20	)		(22	)
Other		—			(552	)		144			(556	)
Investment gains (losses)		4,851			31,625			37,235			2,032
Derivative contract gains (losses)		70			(43	)		780			(640	)
	$	4,921		$	31,582		$	38,015		$	1,392

Equity securities gains and losses include unrealized gains and losses from changes in fair values during the period on equity securities we still own, as well as gains and losses on securities we sold during the period. As reflected in the Consolidated Statements of Cash Flows, we received proceeds from sales of equity securities of approximately $12.0 billion in the first nine months of 2021 and $28.6 billion in the first nine months of 2020. In the preceding table, investment gains and losses on equity securities sold during the period represent the difference between the sales proceeds and the fair value of the equity securities sold at the beginning of the applicable period or, if later, the purchase date. Our taxable gains/losses on equity securities sold are generally the difference between the proceeds from sales and original cost. Taxable gains in the third quarter and first nine months of 2021 were $941 million and $2.9 billion, respectively, and were $3.9 billion and $666 million in the third quarter and first nine months of 2020, respectively.

The derivative contract gains and losses derive from equity index put option contracts written prior to March 2008 on four major equity indexes. Information related to these contracts follows (dollars in millions).

Notional value in the preceding table represents the aggregate undiscounted amounts payable assuming the value of each index is zero at each contract’s expiration date. Intrinsic value is the undiscounted liability assuming the contracts are settled based on the index values and foreign currency exchange rates as of the balance sheet date. Substantially all open contracts as of September 30, 2021 will expire by February 2023. Future payments, if any, under any given contract will be required if the index value is below the contract strike price at the contract expiration date. We received aggregate premiums on the contract inception dates of $1.5 billion with respect to unexpired contracts as of September 30, 2021 and we have no counterparty credit risk.