ECNs and exchanges are usually known to traders by a three- or four-letter designators, which identify the ECN or exchange on Level II stock screens. The first of these was Instinet (or "inet"), which was founded in 1969 as a way for major institutions to bypass the increasingly cumbersome and expensive NYSE, and to allow them to trade during hours when the exchanges were closed. Early ECNs such as Instinet were very unfriendly to small investors, because they tended to give large institutions better prices than were available to the public. This resulted in a fragmented and sometimes illiquid market.
By holding overnight, the swing trader incurs the unpredictability of overnight risk such as gaps up or down against the position. By taking on the overnight risk, swing trades are usually done with a smaller position size compared to day trading (assuming the two traders have similarly sized accounts). Day traders typically utilize larger position sizes and may use day trading margin of 25%.
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.