When a trader trades with a broker, the broker must close a position in the market to protect him against exchange rate risk. Scalpers often trade hundreds of transactions in a short time. Even though brokers get income from the spread in this transaction, trades that often make it difficult for brokers to properly assess their position and cover them on the market. Moreover, brokers must often do coverage. Because of this many brokers don't like brokers. Some brokers don't allow scalping, I think brokers are market makers. In normal account brokers do not allow, in scalping it is very difficult and risky, when we get a profit through good scalping but the market broker's server will be busy and pay money from his pocket. If it's an ECN account and STP, then we can do this type of scalping because it connects this type of account from the market, so we get a profit and attract the bank to pay the broker and then they will transfer us. Because in the ECN brokerage account and STP only has 1 role only the account so that is why brokers do not have a head to pay profit.