CFDs are a leverage product and can involve a significant risk of loss. Trading CFDs may not be suitable for all, therefore you should ensure that you understand the risks involved and take into account your individual circumstances.
Trader's Glossary

What is Margin Level?

Margin level is the margin that a trader has available to open further positions. Expressed as a percentage, it is the ratio of equity to used margin. When it drops to 100% this means that all available margin is in use and no further trades may be opened. It is calculated as follows: Margin Level = Equity / Margin * 100.