Contrary to a European-style option, the right to exercise an American-style option can be exerted at any time up to the expiry date.
Issuers continually post prices at which they will buy or sell their own products, thereby ensuring the tradability of those securities even if there is little or no turnover taking place otherwise in the marketplace. At the current "ask" price, you can buy a structured product such as a warrant or certificate from the issuer at any time during its term to maturity (exception: the issue is totally sold out). In most instances, the ask price is somewhat higher than the bid price.
|At the money||
An option or warrant is "at the money" when the current market price of the underlying instrument is in the proximity of the strike price.