Investors have ridden artificial intelligence darling Nvidia to soaring returns over the past 18 months, but some notable investors have called time on the rally before the US chipmaker’s next batch of earnings.

Alex Pollak, co-founder and investment chief of Sydney-based Loftus Peak, first bought Nvidia in 2016 – when the shares traded for less than $US30 apiece (they now trade at $US943.59) – but has more than halved his stake in the company as well as in fellow chipmaker AMD in the past six months.