Stock-style margining
requires the purchaser to pay the full option premium at the time of
purchase. The purchaser has no further financial obligations, and the
risk of loss is limited to the purchase price and transaction costs.
Futures-style margining requires the purchaser to pay initial margin
only at the time of purchase. The option position is marked to market,
and gains and losses are collected and paid daily. The purchaser's risk
of loss is limited to the initial option premium and transaction costs.
    An individual granting options under either a stock-style or
futures-style system of margining should understand that he or she may
be required to pay additional margin in the case of adverse market
movements.