Unregulated monopoly

Can anyone help me in explanation the difference between regulated and unregulated monopoly?

A regulated monopoly would be where you only have one choice for electricity due to government regulations. An unregulated monopoly would be where a company has cornered the market on a product through acquisition or business practice. For example, imagine if you bought every oil refinery in the country and then proceeded to double the price of gasoline. That would be an unregulated monopoly.