I've heard both sides of this argument and I don't
Post# of 22940
In the standard stock world and "lot" is 100 shares. Everything that happens on the NYSE happens in penny land, just on a different scale plus it is harder to detect.
Yes, shorting does happen, it just happens with larger numbers of shares. When looking at stocks, I'm noticing that the dollar amount of trades, on average, stay roughly the same, regardless of venue. The share amounts change to match the $ the trader has available to trade/invest.