Wallis signed up with Millennium in March 2023 but has only just started in the new gig after taking gardening leave, market sources say.
He is well known in equities circles, thanks to his years in hedge fund sales, followed by long/short investing.
Before joining Millennium, he was a portfolio manager at Hong Kong-based Polymer Capital, which was founded by former Point72 Asia head Angus Wai in 2019 and has since grown to be one of the biggest hedge funds operating in Australia.
Other Australians on Millennium’s team include Mark Samter, who defected from MST around June, and ANZ’s former head of Australian economics David Plank.