When trading shares, it is useful to understand the bid-offer spread as the price of which you buy or sell a share may not exactly match the real-time price of the share on the market.

The bid-offer spread is the difference or spread between the price at which an investor can sell shares versus the price at which an investor can buy share sells respectively. The bid-offer spread allows the market maker to generate revenue from a trade.

Shares that are not popular and trading infrequently tend to have a larger bid-offer spread than those stocks which are regularly traded, such as those on the FTSE 100.