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Supplemental Agreement

The following forms are required if an amendment is made to the Prime Agreement and is still within the advertised scope of work. 

1. Submit Proposal Package for a Supplemental Agreement: All requirements are submitted to the appropriate Project Manager unless otherwise noted below.


*Submitted to

Facilities Capital Cost of Money

This table shows weighted averages of interest rates published by the US Treasury under Public Law 92-41. This rate is used for calculating Facilities Capital Cost of Money under 48 CFR 31.205-10. The table shows a weighted average of six-month rates applicable to various fiscal year ends.

The use of a weighted average rate applied to the average net book value of eligible property plant an equipment is appropriate for firms that have not had unusual fluctuations in capital asset balance during the year.

 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012
 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012

2. Submit Subconsultant related documentation: The prime firm must upload subconsultant disclosure forms and copies of subconsultant agreements to the Vendor Documents Database for each project they have been selected for.

Please note: It is the prime’s responsibility to collect and upload prime and subconsultant continuing disclosures forms. These forms should be submitted starting at the end of the fiscal year (June) and should be uploaded by the beginning of the new fiscal year (July).

3. Multi-Year Contract Certification. The Illinois Procurement Code requires that every person who has entered into a multi-year contract and every subcontractor with a multiyear subcontract shall certify, by July 1 of each fiscal year covered by the contract after the initial fiscal year, to the responsible chief procurement officer whether it continues to satisfy the certification requirements of Article 50 pertaining to eligibility for a contract award. 30 ILCS 500/50-2. To view the certifications and additional requirements of Article 50 click here. Please fill out the form below:

4. Highway Procurement Policy Review (HPPR): To view active engineering, architectural, professional service agreements, and/or supplemental agreements please navigate to HPPR.