As the US equity market hits a new record and stocks such as Tesla and Apple soar, one British fund manager is profiting mightily from the surge — and leaving commentators wondering how long its remarkable run can continue.

The Scottish fund manager Baillie Gifford has become well-known in recent years for its high-profile backing of Tesla — its 6.3% stake makes it the electric carmaker’s second-biggest shareholder behind CEO Elon Musk — and its longstanding bets on top-performing tech stocks, which predate the recent Covid-19 crash and recovery.