That's the opposite of front-running. If the brokerage or HFT was front-running, you would pay more to buy or sell than e.g. Goldman Sachs would. But payment fo

That's the opposite of front-running. If the brokerage or HFT was front-running, you would pay more to buy or sell than e.g. Goldman Sachs would. But payment for order flow means you pay less, because the brokerage is confident that as a retail investor you don't have an edge -- there is no risk of you buying just before the price shoots up and leaving them at a loss.