ASGN Inc — Director's Dealing 2011

Apr 4, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ON ASSIGNMENT INC (ASGN)
CIK: 0000890564
Period of Report: 2011-04-02

Reporting Person: DAMERIS PETER T (Director, President & CEO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-04-02	Common Stock	D	919	$9.99	Disposed	608858	Direct
2011-04-04	Common Stock	M	17188	$5.11	Acquired	626046	Direct
2011-04-04	Common Stock	M	14970	$6.68	Acquired	641016	Direct
2011-04-04	Common Stock	M	36718	$5.22	Acquired	677734	Direct
2011-04-04	Common Stock	M	2734	$4.45	Acquired	680468	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-04-04	Incentive Stock Option (right to buy)	$4.45	M	2734	Disposed	2014-09-27	Common Stock (2734)	Direct
2011-04-04	Incentive Stock Option (right to buy)	$5.11	M	17188	Disposed	2014-03-23	Common Stock (17188)	Direct
2011-04-04	Incentive Stock Option (right to buy)	$5.22	M	36718	Disposed	2013-11-12	Common Stock (36718)	Direct
2011-04-04	Incentive Stock Option (right to buy)	$6.68	M	14970	Disposed	2015-08-29	Common Stock (14970)	Direct

Footnotes

F1: Executive officer elected to satisfy tax withholding obligations upon vesting by having On Assignment, Inc. withhold a number of vested shares equal to that of the employee's tax liability.

F2: These options vest one twenty-fourth on November 27, 2004, and one forty-eighth of such amount with respect to each month thereafter.

F3: These options vest one-fourth of the total number of shares on November 3, 2004, and one forty-eighth of such amount with respect to each month thereafter.

F4: These options vest one forty-eighth after one month from the grant date, and one forty-eighth of such amount with respect to each month thereafter.