(FINANCE) the situation in which a derivatives trader with a short position is wrong about the behavior of the market. Having sold shares of stock he doesn't own, he is now compelled to buy them at a higher price than he sold them for (in order to reimburse whomever he borrowed the shares from).
If the short position was taken by writing naked options (i.e., issuing call options of stock the trader doesn't happen to have), then the trader has to buy shares of underlying stock in order to honor the options.
It's extremely expensive for traders to have to cover their shorts.
The surprising stock rally came as a shock. Nicholas Leeson had been riding high, but now he was furiously covering shorts, and driving the share prices higher still. By closing bell, he was ruined.
(FINANCE) using financial derivatives to guarantee against losses. Typically used by non-traders, such as companies engaged in international commerce, to protect themselves against foreign exchange risk (i.e., the possibility that a customer's currency will decline in value).
BILL: You know, I think that financial derivatives are just a huge sinkhole. The people who trade them are just a bunch of wankers who move bits of paper around but add nothing of value.
ANNA: Well, they do provide some important benefits.
BILL: Name one.
ANNA: Covering risk, for one. If you're an airline, you need those aviation fuel options.