The Tx costs of a trade will probably yield a rebate but they will need to move significant volume to generate enough revenue to cover their other costs. There

The Tx costs of a trade will probably yield a rebate but they will need to move significant volume to generate enough revenue to cover their other costs. There would be no commission if they sold their flow. The only other way to make money here is to internalize even further and give bad fills or jack up other fees.