AVALONBAY COMMUNITIES INC — Director's Dealing 2010

May 7, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AVALONBAY COMMUNITIES INC (AVB)
CIK: 0000915912
Period of Report: 2010-05-05

Reporting Person: Dunn Lili F (Senior Vice President)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-05-05	Common Stock, Par value $.01 per share	M	6023	$44.42	Acquired	31722.3287	Direct
2010-05-05	Common Stock, Par value $.01 per share	M	6989	$34.94	Acquired	38711.3287	Direct
2010-05-05	Common Stock, Par value $.01 per share	M	15760	$49.09	Acquired	54471.3287	Direct
2010-05-05	Common Stock, Par value $.01 per share	M	15902	$67.86	Acquired	70373.3287	Direct
2010-05-05	Common Stock, Par value $.01 per share	S	37092	$105.5322	Disposed	33281.3287	Direct
2010-05-05	Common Stock, Par value $.01 per share	M	20448	$96.19	Acquired	53729.3287	Direct
2010-05-05	Common Stock, Par Value $.01 per share	S	19409	$107.00	Disposed	34320.3287	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-05-05	Stock Options (Right to Buy)	$44.42	M	6023	Disposed	2012-02-13	Common Stock (6023)	Direct
2010-05-05	Stock Options (Right to Buy)	$34.94	M	6989	Disposed	2013-02-12	Common Stock (6989)	Direct
2010-05-05	Stock Options (Right to Buy)	$49.09	M	15760	Disposed	2014-02-12	Common Stock (15760)	Direct
2010-05-05	Stock Options (Right to Buy)	$67.86	M	15902	Disposed	2015-02-11	Common Stock (15902)	Direct
2010-05-05	Stock Options (Right to Buy)	$96.19	M	20448	Disposed	2016-02-09	Common Stock (20448)	Direct

Footnotes

F1: The amount of securities owned following the reported transaction reflects direct ownership of all shares of common stock, including restricted shares.

F2: This transaction was executed in multiple trades at prices ranging from $105.26 to $105.91. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

F3: The options exercised were included in options granted under the issuer's stock option and incentive plan on February 13, 2002, which become exercisable in three equal annual installments beginning on February 13, 2003.

F4: Following the reported transaction, the reporting person held a total of 88,275 options to purchase the issuer's common stock granted on various dates and with varying exercise prices and vesting dates.

F5: The options exercised were included in options granted under the issuer's stock option and incentive plan on February 12, 2003, which become exercisable in three equal annual installments beginning on February 12, 2004.

F6: Following the reported transaction, the reporting person held a total of 81,286 options to purchase the issuer's common stock granted on various dates and with varying exercise prices and vesting dates.

F7: The options exercised were included in options granted under the issuer's stock option and incentive plan on February 12, 2004, which became exerciseable in three equal annual installments beginning on February 12, 2005.

F8: Following the reported transaction, the reporting person held a total of 65,526 options to purchase the issuer's common stock granted on various dates and with varying exercise prices and vesting dates.

F9: The options exercised were included in options granted under the issuer's stock option and incentive plan on February 11, 2005 which became exercisable in three equal installments beginning on February 11, 2006.

F10: Following the reported transaction, the reporting person held a total of 49,624 options to purchase the issuer's common stock granted on various dates and with varying exercise prices and vesting dates.

F11: The options exercised were included in options granted under the issuer's stock option and incentive plan on February 9, 2006, which became exercisable in three equal annual installments beginning on February 9, 2007.

F12: Following the reported transaction, the reporting person holds a total of 29,176 options to purchase the issuer's common stock granted on various dates and with varying exercise prices and vesting dates.