trading strategy that involves buying and selling either call or put
options that have the same expiration date but different strike prices.
"vertical option spread." YourDictionary, n.d. Web. 15 August 2018. <http://www.yourdictionary.com/vertical-option-spread>.
vertical option spread. (n.d.). Retrieved August 15th, 2018, from http://www.yourdictionary.com/vertical-option-spread