Gap

Used as a verb to describe a period when the market is moving by wide margins suddenly. I'm not sure where the term comes from, although I always assumed it had its origins in technical analysis. On a candlestick chart of spreads or yields, a day where some bond has a "gap" move will look like a disconnect rather than a continuous trend.

Example: Stories that New Century may declare bankruptcy as early as today has financial spreads gapping wider. (Translation: financial bonds spreads are increasing at a rapid pace.)

If a bond's spread is gapping wider or tighter, that suggests a fundamental change in the market's view of the bond's risk. If the whole market is gapping, that indicates a broad repricing of risk.

The opposite would be a leak.