These developments heralded the appearance of "market makers": the NASDAQ equivalent of a NYSE specialist. A market maker has an inventory of stocks to buy and sell, and simultaneously offers to buy and sell the same stock. Obviously, it will offer to sell stock at a higher price than the price at which it offers to buy. This difference is known as the "spread". The market maker is indifferent as to whether the stock goes up or down, it simply tries to constantly buy for less than it sells. A persistent trend in one direction will result in a loss for the market maker, but the strategy is overall positive (otherwise they would exit the business). Today there are about 500 firms who participate as market makers on ECNs, each generally making a market in four to forty different stocks. Without any legal obligations, market makers were free to offer smaller spreads on electronic communication networks than on the NASDAQ. A small investor might have to pay a $0.25 spread (e.g. he might have to pay $10.50 to buy a share of stock but could only get $10.25 for selling it), while an institution would only pay a $0.05 spread (buying at $10.40 and selling at $10.35).
Simple Scalping Strategy could be a powerful 1-minute scalping system as well and if you try in on the time frame let us know your results! We could use the best scalping strategy indicator (volume) and have a whole basket of strategies to use with it. The reason is that it can confirm a trend, a can confirm a reversal, and it can show us when there is less interest between buyers and sellers.
Assess how much capital you're willing to risk on each trade. Many successful day traders risk less than 1% to 2% of their account per trade. If you have a $40,000 trading account and are willing to risk 0.5% of your capital on each trade, your maximum loss per trade is $200 (0.005 x $40,000). Set aside a surplus amount of funds you can trade with and you're prepared to lose. Remember, it may or may not happen.