By Elliot Gulliver-Needham Riverstone Energy’s underlying assets per share ticked up seven per cent over the last six months, as the company continued an aggressive share repurchase programme. Riverstone’s monster share buyback programme has helped the energy-focused investment trust outperform its peer group over the past one and three years. The trust’s share price has returned 42.2 per cent over the last year and 105 per cent over the last three, compared to 12 per cent and 28.6 per cent, respectively for the average commodities and natural resources trust. During the month of March alone, …