Some day trading strategies (including scalping and arbitrage) require relatively sophisticated trading systems and software. This software can cost up to $45,000 or more. Many day traders use multiple monitors or even multiple computers to execute their orders. Some use real time filtering software which is programmed to send stock symbols to a screen which meet specific criteria during the day, such as displaying stocks that are turning from positive to negative.
A fast Internet connection, such as broadband, is essential for day trading.
Brokerage
Day traders do not use retail brokers because they are slower to execute trades and charge higher commissions than direct access brokers, who allow the trader to send their orders directly to the ECNs. Direct access trading offers substantial improvements in transaction speed and will usually result in better trade execution prices (reducing the costs of trading). Outside the
Commission
Commissions for direct-access brokers are calculated based on volume. The more you trade, the cheaper the commission is. While a retail broker might charge $10 or more per trade regardless of the trade size, a typical direct-access broker may charge as little as $0.004 per share traded, or $0.25 per futures contract. A scalper can cover such costs with even a minimal gain.
As for the calculation method, some use pro-rata to calculate commissions and charges, where each tier of volumes charge different commissions. Other brokers use a flat-rate, where all commissions charges are based on which volume threshold one reaches.
Spread
The numerical difference between the bid and ask prices is referred to as the bid-ask spread. Most worldwide markets operate on a bid-ask-based system.
The ask prices are immediate execution (market) prices for quick buyers (ask takers) while bid prices are for quick sellers (bid takers). If a trade is executed at quoted prices, closing the trade immediately without queuing would not cause a loss because the bid price is always less than the ask price at any point in time.