Would that increase or decrease the amount of taxes?
The fact that I can't even answer that simple question troubles me.
It shouldn't trouble you. Consider "if you have money coming in." What's "money coming in?" You could tax money transfers, but then my sending $10 from BofA to Citi would invoke a tax. Okay, so if the person on both accounts is the same no tax. Fine. What if some sends $10 from a sole account to a joint account? What if it's from a natural person to their single-member LLC? Et cetera, et cetera.
Broadly speaking, federal income taxes take down about 10% of GDP and payroll taxes a further 6% [1].
[1] https://en.wikipedia.org/wiki/Income_tax_in_the_United_State...
Well, we don't (AFAIK) know the total amount of non-GDP transfers of wealth that occur. If you limit taxed transactions to just the transactions that show up in GDP, then it's equivalent to asking what the current tax-to-GDP ratio is, which is easy to look up (it's much higher than 10%.)