Davidson joined the Edinburgh-based firm in September following her departure from Schroders in July after 14 years at the firm.
Upon her exit, Scott MacLennan took over her responsibilities at the £3.8bn Schroder Global Sustainable Growth fund, which she co-managed with Charles Somers, who remains in the post.
Davidson joined Schroders in 2008 as a graduate on the global and international equities team. She co-managed the Global Sustainable Growth's predecessor, the Global Demographic Opportunities strategy, since its launch in 2010.
Schroders names new co-manager for £3.8bn Global Sustainable Growth fund as Davidson departs
Her new mandated, the Baillie Gifford Global Stewardship Equities fund, launched in 2015 and invests in sustainable growth companies, seeking to identify enduring businesses that make a positive difference to society.
Commenting on Davidson's new role, Ross said: "We are seeing growing interest in sustainable investment. Katherine adds considerable experience and expertise to the team, which will be invaluable as we continue to develop and improve the Global Stewardship Strategy."
