(Sharecast News) - Riverstone Energy updated the market on the three months ended 31 March on Wednesday, reporting a net asset value of $1.22bn, or £937m, at period end.The FTSE 250 company said its net asset value per share on the same date was $15.28 or 1,172p.Its loss for the period totalled $210.2m, making for a basic loss per share of 263.1 US cents.The firm's market capitalisation as at 31 March stood at $977m, or £750m, and its share price at period end was $12.24 or 939p.Total realisations during the period reached $123m, consisting of $83m from Meritage Midstream Services III, $37m from Sierra Oil and Gas, and $3m from Carrier Energy Partners II.Total gross committed capital as at 31 March was $1.47bn, with total net committed capital reaching $1.27bn, or 94% of net capital available.Riverstone said total net capital invested at period end was $1.13bn, or 83% of net capital available.Since inception, the investment-weighted average WTI oil price at 31 March was approximately $51.61 per barrel, the board reported."REL remains focussed on its portfolio construction and utilising a modified investment approach to increase diversification, as demonstrated by its investment in Handy Tankers Ridgebury of up to $22m, and recent commitment of up to $66m to Onyx, a newly formed European independent power producer," said chairman Richard Hayden."These new commitments, as well as the next potential investment in the near-term pipeline, are consistent with this new modified investment approach and are non-ECI investments as such are not subject to US taxes."Following the successful monetisations of Meritage III and Sierra, REL is continuing to evaluate new investments that span the entire energy value chain with an emphasis on the midstream, energy services and power sectors."David M Leuschen and Pierre F Lapeyre Jr, Cc-founders of Riverstone, added that the macro backdrop for the upstream sector had continued to be "challenging", as public indices and trading multiples remained at muted levels."A constructive geopolitical environment and increase in capital markets and M&A activity will be important to a recovery in valuations over the long-term," the pair said in their joint statement.