For strangles (long in this example), an investor will buy an "out of the money" call and an "out of the money" put simultaneously for the same expiry date for the same underlying asset. Investors who use this strategy are assuming the underlying asset (like a stock) will have a dramatic price movement but don't know in which direction. What makes a long strangle a somewhat safe trade is that the investor only needs the stock to move greater than the total premium paid, but it doesn't matter in which direction. 
Based on data from IHS Markit for SEC Rule 605 eligible orders executed at Fidelity between April 1, 2018 and March 31, 20198. The comparison is based on an analysis of price statistics that include all SEC Rule 605 eligible market and marketable limit orders of 100-499 shares for the 100 share figure and 100–1,999 shares for the 1,000 share figure. For both the Fidelity and Industry savings per order figures used in the example, the figures are calculated by taking the average savings per share for the eligible trades within the respective order size range and multiplying each by either 100 or 1000, for consistency purposes. Fidelity's average retail order size for SEC Rule 605 eligible orders (100 -1,999 shares) and (100–9,999 shares) during this time period was 430 and 842 shares, respectively. The average retail order size for the Industry for the same shares ranges and time period was 228 and 333 shares, respectively. Price improvement examples are based on averages and any price improvement amounts related to your trades will depend on the particulars of your specific trade.
A bull call spread, or bull call vertical spread, is created by buying a call and simultaneously selling another call with a higher strike price and the same expiration. The spread is profitable if the underlying asset increases in price, but the upside is limited due to the short call strike. The benefit, however, is that selling the higher strike call reduces the cost of buying the lower one. Similarly, a bear put spread, or bear put vertical spread, involves buying a put and selling a second put with a lower strike and the same expiration. If you buy and sell options with different expirations, it is known as a calendar spread or time spread.
An option is a contract that allows (but doesn't require) an investor to buy or sell an underlying instrument like a security, ETF or even index at a predetermined price over a certain period of time. Buying and selling options is done on the options market, which trades contracts based on securities. Buying an option that allows you to buy shares at a later time is called a "call option," whereas buying an option that allows you to sell shares at a later time is called a "put option." 
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