The NASDAQ has more slippage. (1) NYSE specialists tend to trade in a more stabilizing manner than NASDAQ market makers. (2) NYSE stocks tend to have more institutional participation than NASDAQ issues (ignoring the biggest, large-cap, high-tech issues; i.e. MSFT, INTC, CSCO, ORCL, AAPL et al). Institutional investors are less likely to panic than retail investors. (3) NASDAQ issues without listed options can be more volatile because there's nowhere to hedge. (4) NASDAQ issues tend to attract more "hot money" looking for the next GOOG, QCOM or MSFT. That type of money can get scared easily when bad news comes about and be very emboldened when good news hits the wire. That's just my opinion.