How do you value a put option?

A call option allows its purchaser to buy ("call in") stocks at a certain price on a certain date--say, 100 shares of Walmart for $50 on November 1. A put option allows its purchaser to sell ("put")...

Call options are contracts that allows you to buy a stock at a fixed price no matter what price it is in the future. You usually buy call options if you think a stock is going to go up because you...

A put option is an option in which the buyer has the right but is not required to sell a security to the writer of the contract at the strike price during a certain time period. If the buyer...

Stock options give the right, but not the requirement, to buy or sell shares at a certain price on a certain date. A put option gives its buyer the right to sell, or put, a stock to the put seller. A...

There are three reasons to buy a put option: to lock in downside profits: if you paid $10 for the stock and it's now $20, you could buy a put at $18. If the stock falls past $18, the put exercises...