Money is all fake anyway. It's just artificial score keeping, numbers in a ledger. They are created and destroyed according to arbitrary rules that have little or nothing to do with value. The score doesn't represent a real thing, despite our entire lifetimes spent thinking about it that way.
In the case of the stock market, prices are determined by the balance of willing buyers to willing sellers. The recent tax bill was designed to cause government deficits by returning tax revenue to rich people, on the supposition that they are already too rich to spend it so they will instead invest that money in the stock market. That's increasing the supply of buyers, which should drive up stock prices.
And don't confuse stock market investment with the "allocation of capital" the way so many economic textbooks do. Unless you're investing in an IPO or a new issue, no company makes any money at all when you buy their stock. You're just paying some previous Joe for his stock certificate, which he also bought from some previous Jane, who at some point in ancient history gave money to the company so they could raise capital. How often do you think a DJIA company has an IPO or a new issue? Is it clear yet how ridiculous the whole idea of stock prices is as a gauge of economic progress?
"The Money Supply" is an almost meaningless term. Every time you write a check, you are literally creating money out of thin air. You are exchanging the promise of future payment for goods and services rendered immediately, and it doesn't matter if there's any money in your account when you write the check or not, because you have still effectively caused economic activity to happen. Even if there IS money in your account, the check could go a week or a month before it is deposited and shows up on the ledger, so you have effectively created a week or a month's worth of free money. Collectively we do billions of dollars worth of this imaginary float money at any given moment. It doesn't exist as cash or gold or even ones and zeros, it's just based on trust.
And the biggest asset most of us own is real estate, which is arguably the least liquid but most real asset anyone can think of, is just as bogus. If zillow says my house goes up by $20k this year, did I actually make any money? I can spend that $20k, by taking out a home equity loan or refinancing, but it's also not based on anything except the expectation that in the future someone will pay a larger sum for my property. Did I create wealth with my property just because someone else thinks it is more valuable now?
The more I think about this topic, the more solidly I become convinced that the entire global economy is basically a shell game, a useful sham designed to incentivize our hard work. We can't have everyone out there watching sunsets and holding hands, we need worker bees sitting in cubicles! Money is just the little white numbers in the corner of your NES screen that tells you you're doing a good job, and it's basically just as artificial. Inflation and business cycles and interest rates and stock prices are just quirks, wrinkles in the matrix which is ultimately based on a larger unseen lie. Money isn't real!