Section 511. Coordination with social security benefits

a. A member's
  service retirement or disability  benefit  shall  be  reduced  by  fifty
  percent of the primary social security retirement or disability benefit,
  as  the  case  may  be, commencing at (i) age sixty-two, with respect to
  service retirement benefits which commence at or  before  such  age,  or
  disability benefits paid to a disability retiree who is not eligible for
  or receiving primary social security disability benefits, or (ii) on the
  date  on  which  such  member  first becomes eligible to receive primary
  social security disability benefits, with respect to disability benefits
  paid to a disability retiree who is eligible for primary social security
  disability benefits, or (iii) on the date  such  member  separates  from
  service, if later than age sixty-two.
    b. A member's primary social security retirement or disability benefit
  shall  mean  the  social  security  benefit  computed  as of the time of
  separation from service on benefit levels then in effect.  In  no  event
  shall a benefit payable under this article be reduced as a result of any
  increase in social security benefits which occurs after the day on which
  such   member   last  separated  from  service.  Provided,  however,  in
  determining the applicable date pursuant to the preceding sentence,  any
  period  of  service  immediately  prior to such separation which was not
  allowable as credited service pursuant to section five hundred  thirteen
  shall be disregarded.
    c.  1.  A  member's  primary  social security retirement or disability
  benefit, for offset purposes,  shall  be  the  member's  federal  social
  security  primary  insurance amount, calculated as hereinafter provided.
  In determining a member's  primary  insurance  amount,  only  wages  for
  service  with  a  public employer shall be included during years of such
  service, and zero earnings shall be used for  all  other  years  in  the
  member's  federal  social security benefit computation period. Provided,
  however, that a member's primary insurance  amount  shall  in  no  event
  exceed the amount determined pursuant to paragraph two.
    2.  A member's primary insurance amount shall be determined under this
  paragraph if a lower amount  would  thereby  result.  In  determining  a
  member's primary insurance amount hereunder, only wages for service with
  a  public  employer  shall be included during years of such service. The
  member's highest annual wage earned during  any  calendar  year  of  the
  final  five  calendar  years  of service with a public employer shall be
  used for all years of  the  member's  federal  social  security  benefit
  computation  period, if any, falling after such member's separation from
  such service up  to  age  sixty-two  if  separation  occurs  before  age
  sixty-two. Such highest annual wage shall be used for the final calendar
  year  of  service  and,  reduced  by five percent per year for each year
  preceding such final calendar year of service, shall  be  used  for  all
  years of the applicable social security benefit computation period which
  precede  the  final calendar year of such member's service with a public
  employer. The primary insurance amount, as determined  above,  shall  be
  then  reduced  by  a fraction, the numerator of which shall be the total
  years and parts thereof (measured in months) of service  with  a  public
  employer,  and  the  denominator  of  which shall be the total number of
  years in the member's social security benefit computation period.
    d. The member's primary social security disability benefit, for offset
  purposes,  shall  equal  the  member's  primary  insurance  amount.  The
  member's   primary   social  security  retirement  benefit,  for  offset
  purposes, shall equal the member's primary insurance amount
    (i) reduced by five-ninths of one percent  for  each  month,  or  part
  thereof,  that  separation  from  service  upon  retirement (or the date
  benefits commence, if later)  precedes  attainment  of  age  sixty-five,

  provided  that such reduction, in no event, shall exceed twenty percent,
  or
    (ii)  increased  by  one-twelfth  of  one  percent for each month that
  separation from  service  upon  retirement  exceeds  attainment  of  age
  sixty-five.
    e.  Except  as otherwise provided herein, a member's primary insurance
  amount shall be determined as provided in the  federal  social  security
  act, and the rules and regulations promulgated thereunder.
    f.  This  section  shall not apply to general members in the uniformed
  correction force of the New York city department  of  correction  or  to
  uniformed  personnel  in  institutions  under  the  jurisdiction  of the
  department of correctional  services  and  security  hospital  treatment
  assistants,  as  those  terms  are  defined  in subdivision i of section
  eighty-nine of this chapter.
    * NB Expires June 30, 2011