GASB 45, or GASB Statement 45, is an accounting and financial reporting provision requiring government employers to measure and report the liabilities associated with (other than pension) postemployment benefits (or OPEB).
Government employers required to comply with GASB 45 include all states, towns, education boards, water districts, mosquito districts, public schools, and all other government entities that offer OPEB and report under GASB.
The AMM was designed to provide a lower cost option for organizations with fewer than 100 plan members.
Several online resources are available from credible consulting firms (e.g., Gabriel Roeder Smith, Milliman).
This approach is typically less expensive and was developed by the Governmental Accounting Standards Board.