In layman terms, if a person buys a single share it should have the least impact possible on the price, and if a person buys the entire market's worth of shares the price should theoretically go to infinity. Any Marginal volume purchased should always be positively correlated with price movement upwards.
The same goes for selling in the other direction.
Any "proprietary trading" algorithm that violates this simple rule IS NOT MARKET MAKING. How simple is that? An algorithm that continuously alters the correlation between volume and price movement is NOT MARKET MAKING.
Plus, any application of game theory in market making algorithms is illegal collusion.
So the Volcker Rule exception for market making should have very narrow application.
The same goes for selling in the other direction.
Any "proprietary trading" algorithm that violates this simple rule IS NOT MARKET MAKING. How simple is that? An algorithm that continuously alters the correlation between volume and price movement is NOT MARKET MAKING.
Plus, any application of game theory in market making algorithms is illegal collusion.
So the Volcker Rule exception for market making should have very narrow application.