The Uptick Rule was put in place with the S.E.C. Act of 1933 & 1934. It was enacted to prevent “bear-raids” on stocks. Syndicates could sell short a stock and continue selling it thereby driving it down in price dramatically. This was part of the Crash of 1929. The Uptick Rule stopped these “bear-raids.” F.Y.I.: The Uptick Rule was eliminated in 2008. This is part of the reason you can see “mini flash-crashes” in stocks today.