Edelman, who joined in 2008 as an investment analyst, became a fund manager in September 2010, when she took on the newly created US Income Fund which now stands at £21.7m.
James Hackman, who manages the European Income Fund, will assume managerial responsibility for the US Income Fund after a transition period. He will work closely with head of US equities Felix Wintle.
“Whilst we are very sorry to lose Rebecca, it is a testament to her first class research skills, developed at Neptune, that she has been selected for such a key role at this major FTSE consumer group,” deputy managing director Richard Green said.
In the time Edelman managed the fund, it showed a cumulative performance of 33.3% over three years, compared to a 33.5% performance of the North American Retail sector, according to FE analytics.