NGOs accused Glencore of tax evasion and involvement in corruption. “Publish What You Pay” named Glencore the most opaque mining company in terms of tax transparency as they incorporated half of their 46 subsidiaries into tax havens.
Several other NGOs filed a complaint with the OECD in 2011, alleging that Mopani Copper Mines manipulated financial accounts to evade taxation in Zambia.
In the spring of 2012, the British Parliament’s International Development Committee  opened an inquiry over taxation in developing countries  in which Glencore’s subsidiaries in Zambia  and DRC were included.
But Glencore uses taxing tricks not only in developing countries. A British tax expert alleged the company of raising costs of its UK based subsidiary through buying complex insurance contracts with the parent in low-tax Switzerland worth 122.8 m US$.