This excerpt taken from the EQR 10-Q filed May 8, 2008.
3.2 Commencement of Participation
An Eligible Employee or Eligible Trustee shall become a Participant in the Plan on the first date as of which an Elective Deferral, Share Deferral, or Matching Deferral is credited to his or her Account.
3.3 Continued Participation
A Participant in the Plan shall continue to be a Participant so long as any amount remains credited to his or her Account.