Private equity firms are again being threatened with higher taxes, as a long-running debate over how to classify their profits again becomes a focus for governments desperate for cash.

But while high-profile buyout firms may seem an easy target, the question is a controversial one. Critics argue that raising the taxes paid by the private equity industry will also hit small partnerships and venture capital, and may not even raise as much revenue as governments hope.

Part of the argument against higher taxes is that they could hinder jobs growth at a time when major economies are struggling with high unemployment rates.