Not just powerful vested interests. Anyone who knows anything about economics knows that transaction taxes are bad for efficiency etc.

Tax wealth for all I care. But don't tax transactions.

(Btw taxing transactions would actually make financial speculation more profitable. Because bid/ask spreads would become wider and prices more volatile.)

> powerful vested interests would probably fight it tooth and nail

Minimum holds are very different from trade taxes. (The latter is stupid for a variety of reasons.) Minimum holds would make market making more profitable.