SAO PAULO, June 3 (Reuters) - Brazilian environmental services provider Ambipar said on Monday it expects its net revenue to rise by 10% until the end of the year, and its core profit margin to increase by at least 3 percentage points in the next 12 months.

Ambipar said in a securities filing it also expects to reach a net debt/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio of 2.5 in the next 12 months, earlier than its previous forecast of by the end of 2026.

In a separate filing, Ambipar - which offers services such as waste management and recovery and response to environmental emergencies - announced a new share buyback program for up to 20.8 million shares to be carried out over the next 18 months. (Reporting by Andre Romani)