as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
why are american-style options worth more than european-style options?
user
ok, my fault for not doing more research. wikipedia explains this well: http://en.wikipedia.org/wiki/option_style#difference_in_value basically, there are some cases where it's advantageous to exercise an american option early.  for non-gold currency options, this is only when the carrying cost (interest rate differential aka swap rate or rollover rate) is high. the slight probability that this may occur makes an american option worth slightly more.
assistant