HB 2520 -- Public School Retirement System Sponsor: Fallert Beginning August 28, 2008, this bill allows part-time teachers working 17 to 20 hours per week to opt out of membership in the Public School Retirement System. The election to opt out must be filed with the board of trustees of the retirement system within 90 days of employment or within 90 days of August 28, 2008, whichever occurs later.Copyright (c) Missouri House of Representatives