Energy investment firm Riverstone Energy Limited (REL), which floated in London in October, said its investment pipeline remains robust as it reported its maiden results as a listed company.REL had a net asset value at the end of December of $1,139m, or $16.04 per share. Since listing on the London Stock Exchange on October 29th, REL has made its first two commitments of $100m in Liberty Resources and $50m in Eagle Energy Exploration, which both target opportunities in the North American exploration and production markets.REL raised $1.23bn, or £760.3m, in capital through its initial public offering (IPO). The company is chaired by former BG Group Chairman Sir Robert Wilson and has a number of other high-profile energy board members including ex-BP boss Lord Browne and former Anadarko Petroleum chief Jim Hackett."It has been a relatively short time since listing but we are pleased to report positive progress. [...] We remain fully focused on delivering the strategy we outlined at IPO," Wilson said.The firm said that there are several current industry "themes" which it is interested in, including the North American shale revolution, under-investment in energy infrastructure, continued pressure for larger companies to rationalise assets, and the growing success rates in deepwater exploration.BC