> Inflation is a measure of the cost of living
The faster your cash loses value, the stronger your incentive to trade it for something else. That something else can be financial assets.
> It's not got loads to do with large-scale, institutional investments
For investors, particularly retail investors, the consumer price index is most relevant. But for whatever it's worth, producer prices are up over 16% in April (7% excluding "foods, energy, and trade services," which jumped over 50% annualized) [1].
To be clear, I'm floating a hypothesis here. I have seen no evidence linking inflation to demand for these companies' shares. (If anything, it should be the inverse.)