Brother, you can start your own broker with as little as 20K and you can be connected directly to a liquidity provider...Since you're trading big monthly volumes I am assuming that you have big trading capital...Anyways, it could be way better for you instead of going to retail brokers and dealing with their endless shit, silly commissions or mark-ups..You can just go to the liquidity provider and get the raw spread/fast execution (scalper's dream).
Not sure if you are manually trading or algo trading, but if it is manual then i would suggest to look at CMC Markets. I find them best in terms of manual execution platforms with very good liquidity and spreads ( with your volume you will get good rebates also ). Worth checking i suppose..
well for automated trading you won't prefer them as they have their own platform to trade ( click and trade kind of )..
but look at their spreads on majors and the touch volume at the best bid/ask is ~3-4 mio ,so literally you are going to get 1-1.4 pips including commissions for most of the majors with good volume. The two things which are important for scalper are spread(including commission ) and touch volume with no slippage ( you can set how much slippage on market order you want..i prefer 0 so that it becomes fill or kill ). Secondly, fully regulated across the globe so no issues with withdrawals ( at-least so far )
These are my 2 cents but of-course everyone has their own preference.
