Day-trading consultant Stefanie Kammerman, aka the The Stock Whisperer, began trading in 1994 and started teaching her techniques in an online chat room, in 2010.Kammerman focuses on tape reading The most consistently popular ETF among day traders is the SPDR S&P 500 ETF (SPY). It isn't uncommon for trades of this ETF to hit 100 million shares per day, and the huge volume allows you to trade smaller or larger position sizes adapted to the volatility. Here are other high volume stocks and ETFs to consider for day trading. Investopedia indicates that “Day Trading is defined as the buying and selling of a security within a single trading day. Ideally, the day trader wants to end the day with no open positions, so they don’t have to risk holding on to a potentially risky position overnight or for a few days.