On the other hand, Nguyen and Tang (2009) find that 1. The 2008 short-sale ban has a ________ (positive or negative or no) impact on the stock prices of the banned stocks in the ban period. 2. The lift (expiration) of the ban has an overall ________ (positive or negative or mixed) impact on the stock prices of the banned stocks. 3. The skewness of stock returns turns to be more _______ (positive or negative) in the post-Ban period. 4. The frequency of extreme negative returns is _______ (larger or smaller) in the Ban period relative to the pre-Ban period. 5. The overall results documented by Nguyen and Tang suggest that the 2008 Ban has a _________ (beneficial or detrimental) effect on the market.