They have
a certain amount of stock left for black and will not replace it when it's sold out.
An option given to a company's employees to buy
a certain amount of stock in the company at a certain price within a specific time period.
If an institution acts as the principal to
a certain amount of stock, a rapidly declining stock price will affect them.
If you own a company and have promised to sell
a certain amount of stocks to an investor at a specific price, you should nail down the details with a Subscription Agreement.
Imagine two banks agree that if the price of oil goes up they will trade
a certain amount of stocks.