Regal Partners’ Charlie Aitken says one force helps explain both, and it is sitting inside most people’s super. Every payday, contributions flow into superannuation and into index funds, and index funds buy shares in proportion to a company’s size, not its value and not its price. Australian super funds now own between a quarter and a third of the local share market, so those flows move it. When money leaves the index, passive funds sell the biggest names in proportion, whatever the value on offer. Charlie Aitken is investment director at Regal Partners, an active fund manager, and his views on index investing reflect that perspective.