RE:RE:London TXP shorting position update.......
In general a short is something you do to profit from shares that you expect will go down because they are overvalued or becausesome bad news (global, regional or local economy; market; sector; or company specific) is expected.
Sometimes there is a short attack in which there is a coordinated (usually loosely) effort by multiple parties to move the share price lower by shorting it and also issuing negative commentary about the company. The hope is to buy back the shares at a much lower price than they were sold for. It is hard to prove any conspiracy in such cases - everyone has the right to decide that a company has poor prospects. And sometimes negative sentiment feeds on itself (as can positiive sentiment).
A huge short position can amplify an up move if the shares start to move quickly upwards on unexpected or better than expected news. Then all the shorts may want to close those positions by buying shares on the market, and if there are not enough willing sellers the share prices moves up further and faster.