RIO DE JANEIRO (Reuters) - The Inter-American Development Bank (IDB) and Brazil's public banks will announce on Thursday the development of an exchange-traded fund (ETF) focused on sustainable investments in the Amazon rainforest, said two people with direct knowledge.

State development bank BNDES, Banco do Brasil and Caixa Economica Federal are part of the initiative, said the sources, who requested anonymity because plans are not public.

The goal, according to the sources, was to launch the "Amazonia Brasil" ETF in capital markets before the COP30 climate conference in the Brazilian city of Belem next year.

The new fund is expected to replicate a yet-to-be-created benchmark index, with resources allocated to sustainable loans in the Brazilian Amazon.

Banco do Brasil, Caixa, BNDES and the IDB did not respond to requests for comment.

Last year, BNDES and the IDB led the launch of a so-called "Green Coalition" to promote financial solutions and encourage sustainable investments in the region.

According to the sources, the IDB will provide technical and financial support to the Brazilian banks for the new ETF.