In the money
The state in which exercising the option right now would leave the holder better off.
How to read the number
Such an option's premium is intrinsic value plus a top-up for the time remaining, so it tracks the underlying almost as closely as the underlying itself.
When the metric lies
Deep in the money an option is expensive and thinly traded: there are few opposing orders, and closing at the theoretical price does not always work.
Also known as: ITM option