The UK stock markets are also known as shares markets locally, the main exchange for shares is the London Stock Exchange which is divided into the FTSE 100 (large caps), FTSE 250 (mid caps) and the AIM (small caps). You would think the majority of volume would be in the FTSE 100 companies, but in the UK the AIM market holds some great volume and can have some great opportunities. As the UK shares market is one of the biggest in the world you will always find a broad range of companies involved in every sector in almost every country.
Penny stocks in the UK, also known as penny shares locally, are very popular with retail traders because they are inexpensive. This allows traders to start a portfolio without needing a lot of capital. They are more speculative and volatile than stocks of well-established companies and can make significant moves in a short period of time. UK penny stocks have a low value, a relatively small market capitalization and the company usually has a short operating history.