Greenpeace, the environmental campaign group, has fired an employee after it group discovered he lost some 3.8 million euros ($5.15 million) of its money in a bet on international currency markets.
The group said the losses were a result of a "serious error of judgement" from an employee in the group's international finance unit, who "acted beyond the limits of their authority and without following proper procedures," in a statement on Sunday night.
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"The Greenpeace International Board has ordered a complete independent audit to determine how the incident took place and to improve internal procedures," they added.
"Greenpeace International entered into contracts to buy foreign currency at a fixed exchange rate while the euro was gaining in strength. This resulted in a loss of 3.8 million euros against a range of other currencies," the group said.
The Netherlands-based organisation, which has campaigned against pollution and deforestation around the world, apologised for the loss and said "every possible action" is being taken to avoid the possibility of a similar mistake taking place in the future.
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They said there is no evidence the employee in question made personal gains from the position and at the time he thought he "was acting in the best interests of the organization".
Greenpeace's annual report for 2013, due to be released in August this year, will show a budget deficit of 6.8 million euros, which includes the 3.8 million euro loss from the failed currency contract.
"We are continuing to explore all options in relation to the error and process failures. We are confident that steps already taken to improve financial controls mean this could not happen again," the group said.
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"The Greenpeace International Board has ordered a complete independent audit to determine how the incident took place and to improve internal procedures," they added.
The organization promised no money would be taken from climate, ocean or rainforest campaigns as a result of the loss and adjustments would be made by amending planned infrastructure investments.
"Greenpeace International had income of 72.9 million euros in 2013 out of a global budget of around 300 million euros. Greenpeace can only exist thanks to the trust supporters place in us. We are extremely grateful for their contributions and are determined to ensure their trust is not misplaced," the group said.
—By CNBC's Jenny Cosgrave: Follow her onTwitter @jenny_cosgrave