Although if you have X in circulation as money, and Y in stock market valuation, you could say Y/(X+Y) of total value is in the stock market.
If the market valuation goes up to Y+Z, you could say money has "entered" the stock market, pushing its share of value to (Y+Z)/(X+Y+Z) even though the money in circulation, X, could be unchanged.
Not sure about that. Money velocity went down a lot. If you pay Apple money, Apple – the company – keeps that money as cash reserves in some form or another. This might be reinvested and circulates a bit more, but is it really spend in the real economy so that average Joe benefits from this?
Yes, when you buy newly issued shares from Apple (rare), cash flows through the stock market into Apple's accounts, but again, no money went 'into' the stock market.
If you're talking about Apple selling devices, then it's another concept entirely.
Yes, although you could argue that money that was transferred from a checking account to a brokerage account has « flowed into » a market, at least for the time it takes to settle any trades and for the counter party to withdraw theirs (since it will not be used for consumption)
If the market valuation goes up to Y+Z, you could say money has "entered" the stock market, pushing its share of value to (Y+Z)/(X+Y+Z) even though the money in circulation, X, could be unchanged.