指期权的购买者有权在期权合约规定的时间内以特定的价格买入一定数量的标的物（即股票、外汇、利率等），且没有必须买入的义务。若投资者认为未来股价上涨，则可买入看涨期权。如果行权日股票价格高于期权合约约定的执行价格，持有者若行权，获得收益；如果行权日股票的价格低于期权合约约定的执行价格，持有者不会行权，此时期权价值为0。
An agreement that gives an investor the right (but not the obligation) to buy a stock, bond, commodity, or other instrument at a specified price within a specific time period.
It may help you to remember that a call option gives you the right to "call in" (buy) an asset. You profit on a call when the underlying asset increases in price.
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