40 ILCS 5/8-230.10
An employee with at least 10 years of creditable service in the Fund may establish service credit for up to 7 years of full-time employment by the Illinois Housing Development Authority for which the employee does not have credit in another public pension fund or retirement system.
To establish service credit under this Section, the employee must apply to the Fund in writing by January 1, 2003 and pay to the Fund, at any time before beginning to receive a retirement annuity under this Article, an amount to be determined by the Fund, consisting of (i) employee contributions based on the salary actually received by the person from the Illinois Housing Development Authority for that employment and the contribution rates then in effect for employees of the Fund, (ii) the corresponding employer contributions, and (iii) regular interest on the amounts in items (i) and (ii) from the date of the service to the date of payment.
40 ILCS 5/8-230.10