Riverstone Holdings has agreed to acquire a 100% stake in Proserv Group from Intervale Capital and other minority shareholders. Capital for the purchase, which is expected to be completed in December, will come from Riverstone Global Energy and Power Fund V, a $7.7 billion fund closed in 2013. Focused on the offshore and subsea markets, Proserv is an engineered products and services company that offers solutions including drilling control systems, subsea production systems, offshore production equipment and marine technology services. In August, the company had been rumored to be up for sale at around £500 million ($804 million). Intervale has backed it since 2008.