Penny sterling
The penny sterling (symbol: p; plural: pence) is a subdivision of pound sterling, the currency for the United Kingdom. It is currently 1⁄100 of a pound, but historically was 1⁄240 of a pound (old penny sterling). Its name is carried by the present British penny.
are often traded in pence rather than pounds. Stock exchanges often use GBX (or GBp) to indicate that this is the case for the given stock rather than the ISO 4217 currency symbol GBP for pound sterling.
...
Wikipedia