The title here is missing a key word compared to the source: it's stock funds that have had more cash invested, not simply stock. So it's true that every stock purchase has a corresponding seller, but the same is not true for stock funds.
thet the funds buy the stocks...
the fund units/shares are simply a convienient wrapper
But they may buy them from an individual, not a fund, in which case there would be a net flow to funds.
Not sure how significant these flows are.
I’ve been wondering about same /similar thing. I keep hearing that increase in m2 supply is ok as long it goes into assets… not sure how it’s ok since cash still stays in circulation