A jumbo share certificate is a single composite share certificate formed by consolidating/aggregating a large number of market lots. This is issued by the company in favour of the custodian of the shares and is used to reduce the problems of multiple share certificates for large trades.

Member brokers of a stock exchange who specialise in buying and selling of specific securities from and to fellow members. Jobbers do not have any direct contact with the public, but they render a useful function of imparting liquidity to the market. A jobber quotes his ‘bid’ price (the price at which he is willing to buy) and ‘ask’ price (the price at which he is willing to sell ).

The difference between the price at which a jobber is prepared to sell and the price at which he is prepared to buy. A large difference reflects an imbalance between supply and demand.