This note outlines the process set out in the annex to the memorandum of understanding between the Conference of the Parties (COP) and the Council of the Global Environment Facility (GEF) on determination of funding for the implementation of the United Nations Framework Convention on Climate Change. It notes that the GEF Trust Fund has been replenished three times since the closure of the pilot phase in 1994 and describes the processes and approaches by which those replenishments took place. The replenishments were based on factors which are clearly described in this note. The note also presents the timeline of the forthcoming fourth replenishment and a possible timeline for inputs by the COP. At the twentieth session of the Subsidiary Body for Implementation (SBI), Parties may wish to consider this note during their deliberations on the implementation of the COP guidance on the second review of the financial mechanism, and decide on the steps to be taken to assess funding needs as an input to the negotiations on the fourth replenishment of the GEF Trust Fund