A call option/warrant confers the right to purchase at a specific point in time (European-style) or during a specific period of time (American-style) a specific amount of a specific underlying security at a specific price. Thus an increasing price for the underlying instrument causes the value of the option right to increase and hence the option, itself. As a result, the purchaser of a call benefits from the price appreciation of the underlying instrument. Call warrants are essentially the securitised form of standardised call options. Consequently, they are easier to trade for private investors.