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<Taxes are unrelated,
there is no economic model relating them

I can come up with a simple exercise that can show taxes can affect investment decisions.

Say we play a coin flip game:
You have to invest 1 dollar to play. If it lands on heads you get $1.50, if it lands on tails you lose your 1 dollar.

In a world with no taxes, you would most definitely play this risky game since the expected outcome is that you profit $0.25: . Invest a dollar and you are expected to go home with $1.25.

But let's say there is a 25% tax on winnings.
Will your decision to invest change? Maybe.
Now your expected profit is . Invest a dollar and you are expected to go home with $1.06.
Not as attractive as an investment.

What if the tax rate increased to 40%?
Your expected profit is now = -$0.05. A loss. Invest a dollar and you are expected to go home with $0.95.
Now a bad investment.




Here is one of the (I'd imagine)100s of formal models relating taxes to investment.

Tax Policy and Investment Behavior by Robert E. Hall and Dale W. Jorgenson