Whall and Nelson joined Investec Asset Management in September 2012 as energy investment specialists and supported George on the strategies since then.
The duo has a combined 38 years of investment and industry experience.
Nelson joined Investec from Guinness Asset Management where he had worked since 2005, most recently as co-portfolio manager of the Guinness Global Energy Fund.
Meanwhile, Whall joined from Newton Asset Management, where he was most recently their lead oil and gas analyst.
Over the past 12 months, the Investec GSF Global Energy Fund has outperformed its sector average by 6.1%, and has consistently outperformed its sector average over 1, 3, 5 and 10 years, according to Lipper data.
George commented: “Charles and Tom are experienced energy investment professionals and are closely aligned with our investment approach to investing in energy equities. Both believe in the importance of a thorough understanding of the underlying commodity price on an energy stock’s performance.
"They also base their portfolio construction on both long-term themes affecting the sector and a deep knowledge of energy company fundamentals."
George remains named manager on a number of other Investec funds and head of the commodities and resources team.