A quantity set per security by the London Stock Echange; the minimum size of transactions up to which market maker quotes must be good for.... more on: Normal market size
This is the maximum number of shares in which you can trade in one transaction, and be guaranteed to get a price between the indicated bid and offer prices.
A value assigned to a security by the Exchange. The NMS indicates the liquidity of that security. For quote-driven securities, the NMS is used to calculate the minimum quote size within which market makers are obliged to trade.